As filed with the Securities and Exchange Commission on March 9, 2015

Registration No. 333-          

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-4

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

NORTHWEST BANCSHARES, INC.

(Exact name of registrant as specified in its charter)

100 Liberty Street

Warren, Pennsylvania 16365

(814) 726-2140

(Address, Including Zip Code, and Telephone Number, Including Area Code, of

Registrant’s Principal Executive Offices)

William J. Wagner

Chairman, President and Chief Executive Officer

100 Liberty Street

Warren, Pennsylvania 16365

(814) 726-2140

(Address, Including Zip Code, and Telephone Number, Including Area Code, of

Agent for Service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after this registration statement becomes effective.

If the securities being registered on this form are to be offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box:  o

If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  o

If this form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

If applicable, place an X in the box to designate the appropriate rule provision relied upon in conducting this transaction:

CALCULATION OF REGISTRATION FEE

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

Table of Contents

[Logo of LNB]

Dear Fellow Shareholder:

On December 15, 2014, the board of directors of LNB Bancorp, Inc. unanimously approved a merger agreement between LNB Bancorp, Inc. and Northwest Bancshares, Inc.  LNB Bancorp, Inc. is holding a special meeting of its shareholders to vote on the proposals necessary to complete the merger between LNB Bancorp, Inc. and Northwest Bancshares, Inc.  If the merger agreement is approved and the merger is subsequently completed, LNB Bancorp, Inc. will merge with and into Northwest Bancshares, Inc.  LNB Bancorp, Inc.’s separate corporate existence will cease and Northwest Bancshares, Inc. will continue as the surviving corporation.

Under the terms of the merger agreement, each outstanding share of LNB Bancorp, Inc. common stock will be converted into the right to receive 1.461 shares of Northwest Bancshares, Inc. common stock, $18.70 in cash, or a mix of Northwest Bancshares, Inc. common stock and cash, subject to certain agreed adjustment and allocation procedures that will result in 50% of LNB Bancorp’s common stock being converted into Northwest Bancshares, Inc. common stock and 50% of LNB Bancorp’s common stock being converted into cash.  For more information, see “Proposal 1—Description of the Merger—Consideration to be Received in the Merger.”

On December 15, 2014, which was the last trading date preceding the public announcement of the proposed merger, the trading price of Northwest Bancshares, Inc.’s common stock was $12.35, which, after giving effect to the 1.461 exchange ratio, has an implied value of approximately $18.04 per share. Based on this price with respect to the stock consideration, and the cash consideration of $18.70 per share, upon completion of the merger, an LNB Bancorp, Inc. shareholder who receives cash for 50% of his or her shares of common stock and receives stock for 50% of his or her shares of common stock would receive total merger consideration with an implied value of approximately $18.37 per share.  As of                             , 2015, the most reasonably practicable date prior to the mailing of this Proxy Statement/Prospectus, the trading price of Northwest Bancshares, Inc.’s common stock was $          , which, after giving effect to the 1.461 exchange ratio, has an implied value of approximately $       per share.  Based on this price with respect to the stock consideration, and the cash consideration of $18.70 per share, upon completion of the merger, an LNB Bancorp, Inc. shareholder who receives cash for 50% of his or her shares of common stock and receives stock for 50% of his or her shares of common stock would receive total merger consideration with an implied value of approximately $                     per share.

The maximum number of shares of Northwest Bancshares, Inc. common stock estimated to be issuable upon completion of the merger is                                   . As a result of the merger, LNB Bancorp, Inc. shareholders who receive stock consideration will become stockholders of Northwest Bancshares, Inc. Following the completion of the merger, former LNB Bancorp, Inc. shareholders will hold approximately                             % of Northwest Bancshares, Inc.’s common stock.

Your board of directors has unanimously determined that the merger agreement and the merger are in the best interests of LNB Bancorp, Inc. and its shareholders and unanimously recommends that you vote “FOR” approval and adoption of the merger agreement and the merger, and “FOR” the advisory, non-binding proposal to approve the merger-related executive compensation to LNB Bancorp’s named executive officers. The Merger cannot be completed unless holders of at least two-thirds of the issued and outstanding shares of common stock of LNB Bancorp, Inc. vote to approve the merger agreement and the merger. Whether or not you plan to attend the special meeting of shareholders, please take the time to vote by completing the enclosed proxy card and mailing it in the enclosed envelope. If you sign, date and mail your proxy card without indicating how you want to vote, your proxy will be counted as a vote “FOR” approval and adoption of the merger agreement and the merger, “FOR” the advisory, non-binding proposal to approve merger-related executive compensation to LNB Bancorp’s named executive officers and “FOR” the approval of an adjournment of the special meeting if necessary or appropriate to solicit additional proxies if there are not sufficient votes to approve and adopt the merger agreement and the merger or to approve the merger-related executive compensation to LNB Bancorp’s named executive officers. If you fail to vote, or you do not instruct your

Table of Contents

broker how to vote any shares held for you in “street name,” it will have the same effect as voting “AGAINST” the merger agreement and the merger, but it will have no effect on the advisory, non-binding proposal to approve merger-related executive compensation to LNB Bancorp’s named executive officers or on the proposal to approve an adjournment of the special meeting.

The accompanying document is being delivered to LNB Bancorp, Inc. shareholders as Northwest Bancshares, Inc.’s prospectus for its offering of Northwest Bancshares, Inc. common stock in connection with the merger, and as a proxy statement for the solicitation of proxies from LNB Bancorp, Inc. shareholders to vote for the approval of the merger agreement and the merger.

This Proxy Statement/Prospectus provides you with detailed information about the proposed merger. It also contains or references information about Northwest Bancshares, Inc. and LNB Bancorp, Inc. and related matters. You are encouraged to read this document carefully. In particular, you should read the “Risk Factors” section beginning on page          for a discussion of the risks you should consider in evaluating the proposed merger and how it will affect you.

Voting procedures are described in this Proxy Statement/Prospectus. Your vote is important and I urge you to cast it promptly.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the Merger or the securities to be issued under this Proxy Statement/Prospectus or determined if this Proxy Statement/Prospectus is accurate or adequate.  Any representation to the contrary is a criminal offense.  The securities we are offering through this document are not savings or deposit accounts or other obligations of any bank or non-bank subsidiary of either of our companies, and they are not insured by the Federal Deposit Insurance Corporation or any other governmental agency.

Proxy Statement/Prospectus dated [document date]

and first mailed to shareholders on or about                                   , 2015

Table of Contents

WHERE YOU CAN FIND MORE INFORMATION

Both Northwest Bancshares, Inc. and LNB Bancorp, Inc. file annual, quarterly and special reports, proxy statements and other business and financial information with the Securities and Exchange Commission (the “SEC”). You may read and copy any materials that either Northwest Bancshares, Inc. or LNB Bancorp, Inc. files with the SEC at the SEC’s Public Reference Room at 100 F Street, N.E., Room 1580, Washington, D.C. 20549, at prescribed rates. Please call the SEC at (800) SEC-0330 ((800) 732-0330) for further information on the public reference room. In addition, Northwest Bancshares, Inc. and LNB Bancorp, Inc. file reports and other business and financial information with the SEC electronically, and the SEC maintains a website located at http://www.sec.gov containing this information. You will also be able to obtain these documents, free of charge, from Northwest Bancshares, Inc. at www.northwestsavingsbank.com under the “Investor Relations” tab and then under “SEC Filings,” or from LNB Bancorp, Inc. by accessing LNB Bancorp, Inc.’s website at www.4lnb.com under the “Investor Relations” tab.

Northwest Bancshares, Inc. has filed a registration statement on Form S-4 to register with the SEC up to 7,412,328 shares of Northwest Bancshares, Inc. common stock. This Proxy Statement/Prospectus is a part of that registration statement. As permitted by SEC rules, this Proxy Statement/Prospectus does not contain all of the information included in the registration statement or in the exhibits or schedules to the registration statement. You may read and copy the registration statement, including any amendments, schedules and exhibits at the addresses set forth below. Statements contained in this document as to the contents of any contract or other documents referred to in this Proxy Statement/Prospectus are not necessarily complete. In each case, you should refer to the copy of the applicable contract or other document filed as an exhibit to the registration statement. This Proxy Statement/Prospectus incorporates by reference documents that Northwest Bancshares, Inc. and LNB Bancorp, Inc. have previously filed with the SEC. They contain important information about the companies and their financial condition. See “Where You Can Find More Information” on page         . These documents are available without charge to you upon written or oral request to the applicable company’s principal executive offices. The respective addresses and telephone numbers of such principal executive offices are listed below:

To obtain timely delivery of these documents, you must request the information no later than [document request date] in order to receive them before LNB Bancorp, Inc.’s special meeting of shareholders.

Northwest Bancshares, Inc. common stock is traded on the NASDAQ Global Select Market under the symbol “NWBI,” and LNB Bancorp, Inc. common stock is traded on the NASDAQ Global Market under the symbol “LNBB.”

Table of Contents

LNB BANCORP, INC.

457 Broadway

Lorain, Ohio 44052

NOTICE OF THE SPECIAL MEETING OF SHAREHOLDERS

TO BE HELD ON [MEETING DATE]

NOTICE IS HEREBY GIVEN that a special meeting of the shareholders of LNB Bancorp, Inc. will be held at [Meeting Location] at                        .m., Eastern Time, on [Meeting Date], for the following purposes:

1.  To consider and vote upon a proposal to approve and adopt the Agreement and Plan of Merger, dated as of December 15, 2014, by and between Northwest Bancshares, Inc. and LNB Bancorp, Inc. (the “Merger “Agreement”), and thereby to approve the transactions contemplated by the Merger Agreement, including the merger of LNB Bancorp, Inc. with and into Northwest Bancshares, Inc. (collectively, the “Merger”);

2.  To consider and vote upon an advisory, non-binding proposal to approve the compensation payable to the named executive officers of LNB Bancorp in connection with the transactions contemplated by the Merger Agreement (the “Merger-Related Executive Compensation”);

3.  To approve one or more adjournments of the special meeting, if necessary or appropriate, to solicit additional proxies if there are not sufficient votes at the time of the special meeting to approve the Merger Agreement and the Merger or to approve the Merger-Related Executive Compensation; and

4.  To transact any other business that may properly come before the special meeting or any adjournment or postponement thereof.

The Merger is described in more detail in this Proxy Statement/Prospectus, which you should read carefully in its entirety before voting. A copy of the Merger Agreement is attached as Appendix A to this Proxy Statement/Prospectus. Only LNB Bancorp, Inc. shareholders of record as of the close of business on [Record Date] are entitled to notice of and to vote at the special meeting of shareholders or any adjournments of the special meeting.

To ensure your representation at the special meeting of shareholders, please follow the voting procedures described in the accompanying Proxy Statement/Prospectus and on the enclosed proxy card. This will not prevent you from voting in person, but it will help to secure a quorum and avoid added solicitation costs. Your proxy may be revoked at any time before it is voted by following the instructions provided in the Proxy Statement/Prospectus.

Lorain, Ohio

[document date]

LNB BANCORP, INC.’S BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT YOU VOTE “FOR” APPROVAL AND ADOPTION OF THE MERGER AGREEMENT AND THE

Table of Contents

MERGER, “FOR” THE APPROVAL OF THE MERGER-RELATED EXECUTIVE COMPENSATION, AND “FOR” THE APPROVAL OF THE ADJOURNMENT PROPOSAL DESCRIBED ABOVE.

DO NOT SEND STOCK CERTIFICATES WITH THE PROXY CARD. YOU WILL RECEIVE A LETTER OF TRANSMITTAL WITH INSTRUCTIONS FOR DELIVERING YOUR STOCK CERTIFICATES UNDER SEPARATE COVER.

YOUR VOTE IS IMPORTANT!

WHETHER OR NOT YOU EXPECT TO ATTEND THE LNB BANCORP, INC. SPECIAL MEETING IN PERSON, LNB BANCORP, INC. URGES YOU TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE BY COMPLETING, SIGNING AND DATING THE ENCLOSED PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED. If your shares are held in the name of a bank, broker or other nominee, please follow the instructions on the voting instruction card furnished to you by such record holder.

If you have any questions concerning the Merger or other matters to be considered at the special meeting, would like additional copies of this Proxy Statement/Prospectus or need help voting your shares, please contact our proxy solicitor:

[proxy solicitor contact information]

Table of Contents

TABLE OF CONTENTS

Table of Contents

QUESTIONS AND ANSWERS ABOUT THE MERGER AND THE SPECIAL MEETING

The following are answers to certain questions that you may have regarding the Merger and the special meeting. We urge you to read carefully the remainder of this Proxy Statement/Prospectus because the information in this section may not provide all the information that might be important to you in determining how to vote. Additional important information is also contained in the appendices to, and the documents incorporated by reference in, this Proxy Statement/Prospectus.

GENERAL QUESTIONS ABOUT THE MERGER

Q:                                  WHY AM I RECEIVING THIS DOCUMENT?

A.                                    Northwest Bancshares, Inc. (“Northwest Bancshares”) and LNB Bancorp, Inc. (“LNB Bancorp”) have agreed to merge under the terms of a Merger Agreement by and between Northwest Bancshares and LNB Bancorp, dated as of December 15, 2014 (the “Merger Agreement”), that is described in this Proxy Statement/Prospectus. A copy of the Merger Agreement is attached to this Proxy Statement/Prospectus as Appendix A. In order to complete the Merger of LNB Bancorp into Northwest Bancshares (the “Merger”), the shareholders of LNB Bancorp must vote to approve and adopt the Merger Agreement and the Merger. LNB Bancorp will hold a special meeting of its shareholders to obtain this approval. This Proxy Statement/Prospectus contains important information about the Merger, the Merger Agreement, the special meeting, and other related matters, and you should read it carefully.

Q:                                  WHO IS BEING ASKED TO APPROVE THE MERGER?

A:                                   LNB Bancorp shareholders are being asked to vote to approve the Merger.

Under Ohio law, which governs mergers involving LNB Bancorp, the Merger cannot be completed unless LNB Bancorp shareholders vote to approve and adopt the Merger Agreement and approve the Merger. By this Proxy Statement/Prospectus, LNB Bancorp’s board of directors is soliciting proxies from LNB Bancorp’s shareholders to obtain this approval at the special meeting of LNB Bancorp shareholders discussed below.

Q:                                  WHAT WILL LNB BANCORP SHAREHOLDERS RECEIVE IN THE MERGER?

A:                                   If the Merger proposal is approved and the Merger is subsequently completed, each outstanding share of LNB Bancorp common stock will be converted into the right to receive either:

·                                          1.461 shares of Northwest Bancshares common stock, plus cash in lieu of fractional shares; or

·                                          $18.70 in cash, without interest.

The above consideration is subject to an allocation process that requires 50% of LNB Bancorp’s shares of common stock to be exchanged for cash and 50% of LNB Bancorp’s common stock to be converted into Northwest Bancshares common stock. Accordingly, allocations of Northwest Bancshares common stock and cash that you receive will depend on the elections made by other LNB Bancorp shareholders.

On December 15, 2014, which was the last trading date preceding the public announcement of the proposed Merger, Northwest Bancshares’ common stock price was $12.35, which, after giving effect to the 1.461 exchange ratio, has an implied value of approximately $18.04 per share. Based on this price with respect to the stock consideration, and the cash consideration of $18.70 per share, upon completion of the Merger, an LNB Bancorp shareholder who receives cash for 50% of his or her shares of common stock and receives stock for 50% of his or her shares of common stock would receive total merger consideration with an implied value of approximately $18.37 per share.  As of                       , 2015, the most reasonably practicable date prior to the mailing of this Proxy Statement/Prospectus, Northwest Bancshares’ common

1

Table of Contents

stock price was $          , which, after giving effect to the 1.461 exchange ratio, has an implied value of approximately $          .  Based on this price with respect to the stock consideration, and the cash consideration of $18.70 per share, upon completion of the Merger, an LNB Bancorp shareholder who receives cash for 50% of his or her shares of common stock and receives stock for 50% of his or her shares of common stock would receive total merger consideration with an implied value of approximately $                     per share.

For more information, see “Proposal 1—Description of the Merger—Consideration to be Received in the Merger.”

Q:                                  HOW DOES THE ALLOCATION PROCESS WORK?

A:                                   Under the terms of the Merger Agreement, LNB Bancorp shareholders may elect to convert their shares into cash, Northwest Bancshares common stock or a mixture of cash and Northwest Bancshares common stock. All elections are further subject to the allocation and proration procedures described in the Merger Agreement, which provide that the number of shares of LNB Bancorp common stock to be converted into Northwest Bancshares common stock must equal 50% of the total number of shares of LNB Bancorp common stock outstanding at the effective time of the Merger and that the number of shares of LNB Bancorp common stock to be converted into cash in the Merger must equal 50% of the total number of shares of LNB Bancorp common stock outstanding at the effective time of the Merger. Neither Northwest Bancshares nor LNB Bancorp makes any recommendation as to whether LNB Bancorp shareholders should elect to receive cash, Northwest Bancshares common stock or a mixture of cash and Northwest Bancshares common stock in the Merger. Each holder of LNB Bancorp common stock must make his or her own decision with respect to such election.

It is unlikely that elections will be made in the exact proportions provided for in the Merger Agreement. As a result, the Merger Agreement describes procedures to be followed if LNB Bancorp shareholders in the aggregate elect to receive more or less of the Northwest Bancshares common stock than Northwest Bancshares has agreed to issue. These procedures are summarized below.

·                                          If Stock Is Oversubscribed: If LNB Bancorp shareholders elect to receive more Northwest Bancshares common stock than Northwest Bancshares has agreed to issue in the Merger, then all LNB Bancorp shareholders who have elected to receive cash or who have made no election will receive cash for their LNB Bancorp shares and all shareholders who elected to receive Northwest Bancshares common stock will receive a pro rata portion of the available Northwest Bancshares shares plus cash for those shares not converted into Northwest Bancshares common stock.

·                                          If Stock Is Undersubscribed: If LNB Bancorp shareholders elect to receive fewer shares of Northwest Bancshares common stock than Northwest Bancshares has agreed to issue in the Merger, then all LNB Bancorp shareholders who have elected to receive Northwest Bancshares common stock will receive Northwest Bancshares common stock and those shareholders who elected to receive cash or who have made no election will be treated in the following manner:

·                                          If the number of shares held by LNB Bancorp shareholders who have made no election is sufficient to make up the shortfall in the number of shares of Northwest Bancshares common stock that Northwest Bancshares is required to issue, then all LNB Bancorp shareholders who elected cash will receive cash, and those shareholders who made no election will receive both cash and Northwest Bancshares common stock in such proportion as is necessary to make up the shortfall.

·                                          If the number of shares held by LNB Bancorp shareholders who have made no election is insufficient to make up the shortfall, then all LNB Bancorp shareholders who made no election will receive Northwest Bancshares common stock and those LNB Bancorp

2

Table of Contents

shareholders who elected to receive cash will receive cash and Northwest Bancshares common stock in such proportion as is necessary to make up the shortfall.

No guarantee can be made that you will receive the amounts of cash and/or stock you elect. As a result of the allocation procedures and other limitations outlined in this document and the Merger Agreement, you may receive Northwest Bancshares common stock or cash in amounts that vary from the amounts you elect to receive.

Q:                                  WHAT ARE THE MATERIAL UNITED STATES FEDERAL INCOME TAX CONSEQUENCES OF THE MERGER TO LNB BANCORP SHAREHOLDERS?

A:                                   Northwest Bancshares and LNB Bancorp have received a legal opinion that the Merger will qualify as a tax-free reorganization within the meaning of Section 368(a) of the Internal Revenue Code. However, the federal tax consequences of the Merger to an LNB Bancorp shareholder will depend primarily on whether a shareholder exchanges the shareholder’s LNB Bancorp common stock solely for Northwest Bancshares common stock, solely for cash or for a combination of Northwest Bancshares common stock and cash. LNB Bancorp shareholders who exchange their shares solely for Northwest Bancshares common stock should not recognize a gain or loss except with respect to cash received in lieu of a fractional share of Northwest Bancshares common stock. LNB Bancorp shareholders who exchange their shares solely for cash should recognize a gain or loss on the exchange. LNB Bancorp shareholders who exchange their shares for a combination of Northwest Bancshares common stock and cash may recognize a gain, but not any loss, on the exchange. The actual federal income tax consequences to LNB Bancorp shareholders of electing to receive cash, Northwest Bancshares common stock or a combination of cash and stock will not be ascertainable at the time LNB Bancorp shareholders make their election because it will not be known at that time how, or to what extent, the allocation and proration procedures will apply.

For a more detailed discussion of the material United States federal income tax consequences of the transaction, please see the section “Proposal 1—Description of the Merger—Material Tax Consequences of the Merger” beginning on page         .

The consequences of the Merger to any particular shareholder will depend on that shareholder’s particular facts and circumstances. Accordingly, you are urged to consult your tax advisor to determine the tax consequences of the Merger to you.

Q:                                  WHAT WILL HAPPEN TO LNB BANCORP AS A RESULT OF THE MERGER?

A:                                   If the Merger is completed, LNB Bancorp will merge into Northwest Bancshares, and LNB Bancorp will cease to exist. Following the Merger, The Lorain National Bank (“Lorain National Bank”), a national bank and wholly-owned subsidiary of LNB Bancorp, will merge with and into Northwest Bank, a Pennsylvania-chartered savings bank and wholly-owned subsidiary of Northwest Bancshares, with Northwest Bank being the surviving bank.

Q:                                  WHEN WILL THE MERGER BE COMPLETED?

A:                                   We expect the Merger will be completed when all of the conditions to completion contained in the Merger Agreement are satisfied or waived, including the receipt of required regulatory approvals and the approval of the Merger Agreement by LNB Bancorp shareholders at the LNB Bancorp special meeting. We currently expect to complete the Merger during the third quarter of 2015. However, because fulfillment of some of the conditions to completion of the Merger, such as the receipt of required regulatory approvals, is not entirely within our control, we cannot predict the actual timing.

3

Table of Contents

Q:                                  WHAT HAPPENS IF THE MERGER IS NOT COMPLETED?

A:                                   If the Merger is not completed, LNB Bancorp shareholders will not receive any consideration for their shares of common stock in connection with the Merger. Instead, LNB Bancorp will remain an independent company and its common stock will continue to be listed and traded on the NASDAQ Global Market. Under specified circumstances, LNB Bancorp may be required to pay to Northwest Bancshares a fee with respect to the termination of the Merger Agreement. Northwest Bancshares may also be required to pay LNB Bancorp a fee with respect to the termination of the Merger Agreement under certain circumstances. For more information, please review the sections entitled “Terminating the Merger Agreement” and “Termination Fee” beginning on page         .

Q:                                  WHERE CAN I FIND MORE INFORMATION ABOUT NORTHWEST BANCSHARES AND LNB BANCORP?

A:                                   You can find more information about Northwest Bancshares and LNB Bancorp from the various sources described under the section entitled “Where You Can Find More Information” at the end of this Proxy Statement/Prospectus.

QUESTIONS AND ANSWERS REGARDING

THE SHAREHOLDERS MEETING

Q:                                  WHEN AND WHERE WILL LNB BANCORP SHAREHOLDERS MEET?

A:                                   LNB Bancorp will hold a special meeting of its shareholders on [Meeting Date], at                      .m., Eastern Time, at [Meeting Location].

Q:                                  WHO CAN VOTE AT THE SPECIAL MEETING?

A:                                   Holders of record of LNB Bancorp common stock at the close of business on [Record Date], which is the record date for the special meeting, are entitled to vote at the special meeting.

Q:                                  HOW MANY VOTES MUST BE REPRESENTED IN PERSON OR BY PROXY AT THE LNB BANCORP SPECIAL MEETING TO HAVE A QUORUM?

A:                                   The holders of at least thirty-three and one-third percent (33 1/3%) of the outstanding shares of LNB Bancorp common stock, present in person or represented by proxy, will constitute a quorum at the special meeting.

Q:                                  WHAT MATTERS ARE LNB BANCORP SHAREHOLDERS BEING ASKED TO APPROVE AT THE LNB BANCORP SPECIAL MEETING PURSUANT TO THIS PROXY STATEMENT/PROSPECTUS?

A:                                  LNB Bancorp shareholders are being asked to approve and adopt the Merger Agreement and approve the transactions contemplated by the Merger Agreement, including the Merger. We refer to this proposal as the “Merger Proposal.”

LNB Bancorp shareholders are also being asked to vote in favor of a non-binding proposal to approve the Merger-Related Executive Compensation.

Finally, LNB Bancorp shareholders are being asked to approve one or more adjournments of the special meeting, if necessary or appropriate, to solicit additional proxies if there are not sufficient votes at the time of the special meeting to approve the Merger Proposal or to approve the Merger-Related Executive Compensation, which we refer to as the “Adjournment Proposal.”

4

Table of Contents

Q:                                  WHAT VOTE BY LNB BANCORP SHAREHOLDERS IS REQUIRED TO APPROVE THE PROPOSALS?

A:                                   Assuming a quorum is present at the LNB Bancorp special meeting, approval of the Merger Proposal will require the affirmative vote of the holders of two-thirds of the outstanding shares of LNB Bancorp common stock entitled to vote on the proposal. Abstentions and broker non-votes will have the same effect as shares voted against the Merger Proposal.

Approval of the LNB Bancorp Merger-Related Executive Compensation will require the affirmative vote of the holders of a majority of the shares of LNB Bancorp common stock represented in person or by proxy at the special meeting. Abstentions will have the same effect as shares voted against the Merger-Related Executive Compensation, but broker non-votes will not affect whether the proposal is approved.

Approval of the Adjournment Proposal will require the affirmative vote of the holders of a majority of the shares of LNB Bancorp common stock represented in person or by proxy at the special meeting. Abstentions will have the same effect as shares voted against the Adjournment Proposal, but broker non-votes will not affect whether the proposal is approved.

As of the record date for the special meeting, directors and executive officers of LNB Bancorp, together with their affiliates, had sole or shared voting power over approximately       % of the LNB Bancorp common stock outstanding and entitled to vote at the special meeting.  Pursuant to the terms of the Merger Agreement, each of the directors and certain executive officers of LNB Bancorp, who own in the aggregate                                  shares of common stock of LNB Bancorp, have entered into voting agreements with Northwest Bancshares to vote their respective shares of LNB Bancorp common stock “FOR” the Merger Proposal.

Q:                                  HOW MAY LNB BANCORP SHAREHOLDERS VOTE THEIR SHARES FOR THE SPECIAL MEETING PROPOSALS PRESENTED IN THIS PROXY STATEMENT/PROSPECTUS?

A:                                   Shareholders may vote by completing, signing, dating and returning the proxy card in the enclosed prepaid return envelope or by following the telephone or Internet voting instructions on the proxy card as soon as possible or by attending the special meeting and voting in person. This will enable your shares to be represented and voted at the special meeting. If your stock is held in street name, you will receive instructions from your broker, bank or other nominee that you must follow to have your shares voted. Your broker, bank or other nominee may allow you to deliver your voting instructions via the telephone or the Internet. Please review the proxy card or instruction form provided by your broker, bank or other nominee that accompanies this Proxy Statement/Prospectus.

Q:                                  WILL A BROKER OR BANK HOLDING SHARES IN “STREET NAME” FOR AN LNB BANCORP SHAREHOLDER AUTOMATICALLY VOTE THOSE SHARES FOR THE SHAREHOLDER AT THE LNB BANCORP SPECIAL MEETING?

A:                                   No. A broker or bank WILL NOT be able to vote your shares with respect to the Merger Agreement and the Merger without first receiving instructions from you on how to vote. If your shares are held in “street name,” you will receive separate voting instructions with your proxy materials. It is therefore important that you provide timely instruction to your broker or bank to ensure that all shares of LNB Bancorp common stock that you own are voted at the special meeting.  The failure of a shareholder whose shares of LNB common stock are held in “street name” to give voting instructions to the broker or bank will have the same effect as a vote “AGAINST” the Merger Proposal.

5

Table of Contents

Q:                                  WILL LNB BANCORP SHAREHOLDERS BE ABLE TO VOTE THEIR SHARES AT THE SPECIAL MEETING IN PERSON?

A:                                   Yes. Submitting a proxy will not affect the right of any shareholder to vote in person at the special meeting. If you hold your hold shares in “street name” and wish to attend the special meeting, you must ask your broker or bank how to vote those shares in person at the special meeting.

Q:                                  MAY AN LNB BANCORP SHAREHOLDER CHANGE OR REVOKE HIS OR HER VOTE AFTER SUBMITTING A PROXY?

A:                                   Yes. If you have not voted through your broker, you can change your vote by:

·                                          providing written notice of revocation to the Corporate Secretary of LNB Bancorp, which must be provided to the Corporate Secretary by the time the special meeting begins;

·                                          submitting a new proxy card (any earlier proxies will be revoked automatically); or

·                                          attending the special meeting and voting in person. Any earlier proxy will be revoked. However, simply attending the special meeting without voting will not revoke your proxy.

If you have instructed a broker to vote your shares, you must follow your broker’s directions to change your vote.

Q:                                  WHAT SHOULD A SHAREHOLDER DO IF HE OR SHE RECEIVES MORE THAN ONE SET OF VOTING MATERIALS?

A:                                   You may receive more than one set of voting materials, including multiple copies of this Proxy Statement/Prospectus and multiple proxy cards or voting instruction cards. For example, if you hold your shares of common stock in more than one brokerage account, you will receive a separate voting instruction card for each brokerage account in which you hold shares. In addition, if you are a holder of record and your shares of common stock are registered in more than one name, you will receive more than one proxy card. Please complete, sign, date and return each proxy card and voting instruction card that you receive or otherwise follow the voting instructions set forth in this Proxy Statement/Prospectus in the sections entitled “Special Meeting of LNB Bancorp, Inc. Shareholders.”

Q:                                  IF A SHAREHOLDER DOES NOT VOTE IN FAVOR OF THE MERGER PROPOSAL, IS HE OR SHE ENTITLED TO DISSENTERS’ RIGHTS?

A:                                  Yes.  If you are an LNB Bancorp shareholder as of [Record Date], the record date for the special meeting, and you do not vote your shares in favor of the Merger Proposal and you do not return an unmarked proxy card, you will have the right under Section 1701.85 of the Ohio General Corporation Law (“OGCL”) to demand the fair cash value for your LNB Bancorp common shares. The right to make this demand is known as “dissenters’ rights.” To exercise your dissenters’ rights, you must deliver to LNB Bancorp a written demand for payment of the fair cash value of your shares of common stock before the vote on the Merger Proposal is taken at the special meeting. The demand for payment must include your address, the number and class of LNB Bancorp common shares owned by you, and the amount you claim to be the fair cash value of your LNB Bancorp shares of common stock, and should be mailed to: LNB Bancorp, Inc., Attention: Robert F. Heinrich, 457 Broadway, Lorain, Ohio 44052. LNB Bancorp shareholders who wish to exercise their dissenters’ rights must: (i) either vote against the Merger Proposal or not return the proxy card, and (ii) deliver written demand for payment prior to the LNB Bancorp shareholder vote. For additional information regarding dissenters’ rights, see “Dissenters’ Rights” and the complete text of the applicable sections of the OGCL attached to this Proxy Statement/Prospectus as Appendix B.

6

Table of Contents

Q:                                  WHAT DOES LNB BANCORP’S BOARD OF DIRECTORS RECOMMEND WITH RESPECT TO THE THREE PROPOSALS?

A:                                   LNB Bancorp’s board of directors has unanimously determined that the Merger Agreement and the Merger are in the best interests of LNB Bancorp and its shareholders and unanimously recommends that LNB Bancorp shareholders vote “FOR” the Merger Proposal.  In addition, LNB Bancorp’s board of directors unanimously recommends that LNB Bancorp shareholders vote “FOR” approval of the Merger-Related Executive Compensation and “FOR” the Adjournment Proposal.

Q:                                  ARE THERE RISKS THAT I SHOULD CONSIDER IN DECIDING WHETHER TO VOTE FOR APPROVAL OF THE MERGER-RELATED PROPOSALS?

A:                                   Yes. You should read and carefully consider the risk factors set forth in the section of this Proxy Statement/Prospectus entitled “Risk Factors” beginning on page         .

Q:                                  WHY ARE LNB BANCORP SHAREHOLDERS BEING ASKED TO APPROVE, ON AN ADVISORY, NON-BINDING BASIS, CERTAIN MERGER-RELATED EXECUTIVE COMPENSATION?

A:                                   The federal securities laws require LNB Bancorp to seek a non-binding advisory vote with respect to certain payments that may be made to LNB Bancorp’s named executive officers under certain existing agreements in connection with the Merger.

Q:                                  WHAT WILL HAPPEN IF LNB BANCORP SHAREHOLDERS DO NOT APPROVE CERTAIN MERGER-RELATED EXECUTIVE COMPENSATION AT THE SPECIAL MEETING?

A:                                   The vote with respect to the Merger-Related Executive Compensation is an advisory vote and will not be binding on LNB Bancorp. Therefore, if the Merger Agreement is approved by LNB Bancorp’s shareholders, the Merger-Related Executive Compensation could still be paid to the LNB Bancorp named executive officers, if and to the extent, required or allowed under applicable law even if LNB Bancorp’s shareholders do not approve the Merger-Related Executive Compensation.

Q:                                  WILL THE MERGER-RELATED EXECUTIVE COMPENSATION BE PAID IF THE MERGER IS NOT CONSUMMATED?

A:                                   No. Payment of the Merger-Related Executive Compensation is contingent upon the consummation of the Merger.

Q:                                  SHOULD LNB BANCORP SHAREHOLDERS SEND IN THEIR STOCK CERTIFICATES NOW?

A:                                  No. LNB Bancorp shareholders SHOULD NOT send in any stock certificates now.  If the Merger is approved, transmittal materials, with instructions for their completion, will be provided to LNB Bancorp shareholders under separate cover and the stock certificates should be sent at that time.

Q:                                  WHAT HAPPENS IF I SELL MY SHARES OF LNB BANCORP COMMON STOCK BEFORE THE SPECIAL MEETING?

A:                                   The record date for LNB Bancorp shareholders entitled to vote at the special meeting is earlier than both the date of the special meeting and the completion of the Merger. If you transfer your shares of LNB Bancorp common stock after the record date but before the special meeting, you will, unless special arrangements are made, retain your right to vote at the special meeting but will transfer the right to receive the merger consideration to the person to whom you transfer your shares.

7

Table of Contents

Q:                                  WHAT DO LNB BANCORP SHAREHOLDERS NEED TO DO NOW?

A:                                   After carefully reading and considering the information contained in this Proxy Statement/Prospectus, we are requesting you vote by mail, by telephone, by Internet or by attending the special meeting and voting in person. If you choose to vote by mail, you should complete, sign, date and promptly return the enclosed proxy card. The proxy card will instruct the persons named on the proxy card to vote your LNB Bancorp shares at the special meeting as you direct. If you sign and send in a proxy card and do not indicate how you wish to vote, the proxy will be voted “FOR” each of the special meeting proposals. Alternatively, you can follow the telephone or Internet voting instructions on your proxy card.

Q:                                  IF I AM AN LNB BANCORP SHAREHOLDER, WHO CAN HELP ANSWER MY QUESTIONS?

A:                                   If you have any questions about the Merger or the special meeting, or if you need additional copies of this Proxy Statement/Prospectus or the enclosed proxy card, you should contact LNB Bancorp’s proxy solicitor,                       , at                         for shareholders or                    for banks and brokers.

8

Table of Contents

SUMMARY

This summary highlights selected information in this Proxy Statement/Prospectus and may not contain all of the information important to you. To understand the Merger more fully, you should read this entire document carefully, including the documents attached to this Proxy Statement/Prospectus.

The Companies

Northwest Bancshares, Inc.

100 Liberty Street

Warren, Pennsylvania 16365-2353

(814) 726-2140

Northwest Bancshares, Inc., a Maryland corporation (“Northwest Bancshares”), is a savings and loan holding company headquartered in Warren, Pennsylvania that was incorporated and commenced operations in 2009. Northwest Bancshares’ common stock is listed on the NASDAQ Global Select Market under the symbol “NWBI.” Northwest Bancshares conducts its operations primarily through Northwest Bank, a Pennsylvania-chartered savings bank founded in 1896 with 162 community banking offices in Pennsylvania, New York, Ohio and Maryland and 51 consumer finance offices in Pennsylvania through its subsidiary, Northwest Consumer Discount Company. Northwest Bank also offers investment management and trust services and, through wholly-owned subsidiaries, actuarial and benefit plan administration services as well as property and casualty and employee benefit plan insurance.  Northwest Bank’s principal lending activities include the origination of fixed-rate loans secured by first and second mortgages on owner-occupied, one- to four-family residences, shorter term consumer loans and commercial business and commercial real estate loans.  Northwest Bank’s principal sources of funds are personal and business deposits, borrowed funds and the principal and interest payments on loans and marketable securities.  At December 31, 2014, Northwest Bancshares had total assets of $7.775 billion, total deposits of $5.633 billion and total stockholders’ equity of $1.063 billion.

LNB Bancorp, Inc.

457 Broadway

Lorain, Ohio 44052

(440) 244-6000

LNB Bancorp, Inc., an Ohio corporation (“LNB Bancorp”), is a bank holding company headquartered in Lorain, Ohio that was incorporated and commenced operations in 1984. LNB Bancorp’s common stock is quoted on the NASDAQ Global Market under the symbol “LNBB.” LNB Bancorp conducts its operations primarily through Lorain National Bank, a national bank founded in 1905 that offers products and services to individuals, families and business through 20 retail banking offices in Lorain, Cuyahoga and Summit counties, Ohio. Lorain National Bank’s principal lending activities are the origination of commercial and industrial loans, commercial real estate loans, residential mortgage loans, indirect loans and installment loans.  Lorain National Bank also offers investment management and trust services.  Lorain National Bank’s principal sources of funds are personal and business deposits, borrowed funds and the principal and interest payments on loans and marketable securities. At December 31, 2014, LNB Bancorp had total assets of $1.237 billion, total deposits of $1.035 billion and total shareholders’ equity of $115.3 million.

Special Meeting of LNB Bancorp, Inc. Shareholders; Required Vote (page         )

A special meeting of LNB Bancorp shareholders is scheduled to be held at [Meeting Location] at                    .m., Eastern Time, on [Meeting Date]. At the special meeting, you will be asked to vote on a proposal to approve and adopt the Merger Agreement and the Merger between LNB Bancorp and Northwest Bancshares, which we refer to as the “Merger Proposal.” You will also be asked to vote on an advisory, non-binding proposal to approve the Merger-Related Executive Compensation. You may also be asked to vote to adjourn the special meeting, if

9

Table of Contents

necessary or appropriate, to solicit additional proxies if there are not sufficient votes at the time of the special meeting to approve the Merger Proposal or to approve the Merger-Related Executive Compensation.

Only LNB Bancorp shareholders of record as of the close of business on [Record Date] are entitled to notice of, and to vote at, the LNB Bancorp special meeting and any adjournments or postponements of the meeting.

Approval of the Merger Proposal requires the affirmative vote of the holders of two-thirds of the outstanding shares of LNB Bancorp common stock entitled to vote on the proposal. Approval of the Merger-Related Executive Compensation proposal will require the affirmative vote of the holders of a majority of the shares of LNB Bancorp common stock represented in person or by proxy at the special meeting, without regard to abstentions.  Approval of the adjournment proposal will require the affirmative vote of the holders of a majority of the shares of LNB Bancorp common stock represented in person or by proxy at the special meeting, without regard to abstentions.  As of [Record Date], the record date for the special meeting, there were                                  shares of LNB Bancorp common stock outstanding and entitled to vote. The directors and executive officers of LNB Bancorp, as a group, beneficially owned                                  shares of LNB Bancorp common stock, representing approximately         % of the outstanding shares of LNB Bancorp common stock as of the record date.  Each of the directors and certain executive officers of LNB Bancorp, who own in the aggregate                      shares of common stock of LNB Bancorp, have entered into voting agreements with Northwest Bancshares to vote their respective shares of LNB Bancorp common stock “FOR” the Merger Proposal at the special meeting.

The Merger and the Merger Agreement (page         )

The merger of LNB Bancorp with and into Northwest Bancshares is governed by the Merger Agreement. The Merger Agreement provides that if all of the conditions are satisfied or waived, LNB Bancorp will be merged with and into Northwest Bancshares, with Northwest Bancshares as the surviving entity. We encourage you to read the Merger Agreement, which is included as Appendix A to this Proxy Statement/Prospectus.

What LNB Bancorp, Inc. Shareholders Will Receive in the Merger (page         )

Under the Merger Agreement, each share of LNB Bancorp common stock will be exchanged for either 1.461 shares of Northwest Bancshares common stock plus cash in lieu of fractional shares or $18.70 in cash, subject to 50% of the total merger consideration consisting of Northwest Bancshares common stock and the remainder consisting of cash. On December 15, 2014, which is the last trading day preceding the public announcement of the proposed Merger, Northwest Bancshares’ common stock price was $12.35, which, after giving effect to the 1.461 exchange ratio, has an implied value of approximately $18.04 per share. . Based on this price with respect to the stock consideration, and the cash consideration of $18.70 per share, upon completion of the Merger, an LNB Bancorp shareholder who receives cash for 50% of his or her shares of common stock and receives stock for 50% of his or her shares of common stock would receive total merger consideration with an implied value of approximately $18.37 per share.  As of                         , 2015, the most reasonably practicable date prior to the mailing of this Proxy Statement/Prospectus, Northwest Bancshares’ common stock price was $                  , which, after giving effect to the 1.461 exchange ratio, has an implied value of approximately $                    .  Based on this price with respect to the stock consideration, and the cash consideration of $18.70 per share, upon completion of the Merger, an LNB Bancorp shareholder who receives cash for 50% of his or her shares of common stock and receives stock for 50% of his or her shares of common stock would receive total merger consideration with an implied value of approximately $                     per share.

For more information, see “Proposal 1—Description of the Merger—Consideration to be Received in the Merger.”

10

Table of Contents

Comparative Market Prices (page         )

The following table shows the closing price per share of Northwest Bancshares common stock and the equivalent price per share of LNB Bancorp common stock, giving effect to the Merger, on December 15, 2014, which is the last day on which shares of Northwest Bancshares common stock traded preceding the public announcement of the proposed Merger, and on                                     , 2015, the most recent practicable date prior to the mailing of this Proxy Statement/Prospectus. The equivalent price per share of LNB Bancorp common stock was computed by multiplying the price of a share of Northwest Bancshares common stock by the 1.461 exchange ratio. See “Proposal 1—Description of the Merger—Consideration to be Received in the Merger.”

Recommendation of LNB Bancorp, Inc. Board of Directors (page         )

The LNB Bancorp board of directors has unanimously approved the Merger Agreement and the proposed Merger. The LNB Bancorp board believes that the Merger Agreement, including the Merger, is in the best interests of, LNB Bancorp and its shareholders, and therefore unanimously recommends that LNB Bancorp shareholders vote “FOR” the Merger Proposal. In reaching this decision, LNB Bancorp’s board of directors considered a variety of factors, which are described in the section captioned “Proposal 1—Description of the Merger—Recommendation of the LNB Bancorp board of directors” and “—LNB Bancorp’s Reasons for the Merger”.

In addition, the LNB Bancorp board of directors unanimously recommends that LNB Bancorp shareholders vote “FOR” the advisory, non-binding proposal to approve the Merger-Related Executive Compensation and “FOR” the proposal to adjourn the special meeting to a later date or dates, if necessary or appropriate, to solicit additional proxies if there are not sufficient votes at the time of the special meeting to approve the Merger Proposal or to approve the Merger-Related Executive Compensation

Opinion of LNB Bancorp, Inc.’s Financial Advisor (page         )

In connection with the Merger, the LNB Bancorp board of directors received an opinion, dated December 15, 2014, of Sandler, O’Neill & Partners, L.P. (“Sandler O’Neill”), who acted as financial advisor to LNB Bancorp, as to the fairness, from a financial point of view and as of the date of such opinion, of the merger consideration in the proposed Merger to be received by the holders of LNB Bancorp common stock.  We encourage you to read the full text of Sandler O’Neill’s written opinion, which is included as Appendix C to this Proxy Statement/Prospectus.

Regulatory Matters Relating to the Merger (page         )

Under the terms of the Merger Agreement, the Merger cannot be completed unless it is first approved by the Federal Deposit Insurance Corporation (the “FDIC”), the Pennsylvania Department of Banking and Securities (the “Department”), and the Board of Governors of the Federal Reserve System (the “Federal Reserve”). Northwest Bancshares has filed the required applications. As of the date of this Proxy Statement/Prospectus, Northwest Bancshares has not received any approvals from these regulators. While Northwest Bancshares does not know of any reason why it would not obtain approval in a timely manner, Northwest Bancshares cannot be certain when or if it will receive regulatory approval.

11

Table of Contents

Conditions to Completing the Merger (page         )

The completion of the Merger is subject to the fulfillment of a number of conditions, including:

·                                          approval of the Merger Agreement by LNB Bancorp shareholders;

·                                          the absence of any order, decree, injunction, statute, rule or regulation that enjoins or prohibits the consummation of the Merger;

·                                          receipt of all required regulatory approvals and the expiration of all statutory waiting periods;

·                                          effectiveness of the registration statement of which this Proxy Statement/Prospectus is a part;

·                                          authorization for listing on the Nasdaq Stock Market of the shares of Northwest Bancshares common stock to be issued in the Merger;

·                                          subject to the materiality standard provided in the Merger Agreement, the continued accuracy of representations and warranties made on the date of the Merger Agreement;

·                                          performance in all material respects by each of Northwest Bancshares and LNB Bancorp of its respective obligations under the Merger Agreement, unless waived by the other party; and

·                                          receipt by Northwest Bancshares and LNB Bancorp of an opinion from their respective legal counsel to the effect that the Merger will be treated for federal income tax purposes as a reorganization within the meaning of Section 368(a) of the Internal Revenue Code.

Terminating the Merger Agreement (page         )

The Merger Agreement may be terminated by mutual consent of Northwest Bancshares and LNB Bancorp at any time prior to the completion of the Merger. Additionally, subject to conditions and circumstances described in the Merger Agreement, either Northwest Bancshares or LNB Bancorp may terminate the Merger Agreement if, among other things, any of the following occur:

·                                          there is a material breach by the other party of any representation, warranty, covenant or agreement contained in the Merger Agreement, which breach cannot be cured prior to the closing date, or has not been cured within 30 days after the giving of written notice to such party of such breach;

·                                          the Merger has not been consummated by September 30, 2015, unless the failure to complete the Merger by that time was due to such party’s material breach of any representation, warranty, covenant or other agreement provided in the Merger Agreement, and further provided that this date shall be extended to December 31, 2015 if the inability to complete the Merger is solely due to delay in receiving required regulatory approvals;

·                                          LNB Bancorp shareholders do not approve the Merger Agreement at the LNB Bancorp special meeting; or

·                                          a required regulatory approval is denied or a governmental authority prohibits the consummation of the Merger.

Northwest Bancshares also may terminate the Merger Agreement if LNB Bancorp materially breaches its agreements regarding the solicitation of other acquisition proposals and the submission of the Merger Agreement to shareholders, or if the board of directors of LNB Bancorp does not recommend approval of the Merger Agreement

12

Table of Contents

in this Proxy Statement/Prospectus or withdraws, qualifies or modifies its recommendation in a manner adverse to Northwest Bancshares. LNB Bancorp may also terminate the Merger Agreement if it receives a superior proposal from a third party that the LNB Bancorp board of directors determines, after consultation with its legal and financial advisors, it must accept in the exercise of its fiduciary duties to the LNB Bancorp shareholders, and LNB Bancorp has otherwise complied with the terms of the Merger Agreement.

Termination Fee (page         )

Under certain circumstances described in the Merger Agreement, in connection with the termination of the Merger Agreement, LNB Bancorp will owe Northwest Bancshares a $7.3 million termination fee.  Northwest Bancshares will owe LNB Bancorp a $3.65 million termination fee if the Merger Agreement is terminated because a required regulatory approval is denied solely due to regulatory concerns related to Northwest Bancshares and its subsidiaries. See “Proposal 1—Description of the Merger—Termination Fee” on page          for a list of the circumstances under which a termination fee is payable.

Interests of Certain Persons in the Merger that are Different from Yours (page         )

Officers and directors of LNB Bancorp have employment and other compensation agreements or economic interests that give them interests in the Merger that are somewhat different from, or in addition to, their interests as LNB Bancorp shareholders. These interests and agreements include:

·                                          one member of the LNB Bancorp board of directors will be appointed to the Northwest Bancshares and Northwest Bank boards of directors;

·                                          Northwest Bancshares will establish an advisory board consisting of each of the LNB Bancorp directors, and such advisory directors will serve for an initial term of one year;

·                                          the acceleration of vesting of all outstanding stock options issued by LNB Bancorp, and all such stock options will be exchanged for an amount of cash equal to the positive difference between $18.70 and the exercise price per share of such LNB Bancorp stock option multiplied by the number of shares subject to such LNB Bancorp stock option;

·                                          the acceleration of vesting of outstanding restricted stock awards issued by LNB Bancorp, which the holder will be entitled to exchange for the merger consideration (less any shares withheld to satisfy the tax withholding obligations);

·                                          payments of retention bonuses to certain executive officers of LNB Bancorp;

·                                          severance or other payments to certain executive officers under their employment agreements (assuming such agreements have not expired pursuant to their terms prior to the closing);

·                                          continued employment that has been offered by Northwest Bank to LNB Bancorp’s President and Chief Executive Officer, as well as an acceleration of benefits in a supplemental executive retirement agreement between LNB Bancorp and its President and Chief Executive Officer upon a termination of employment within two years of the Merger; and

·                                          rights of LNB Bancorp officers and directors to continued indemnification coverage and continued coverage under directors’ and officers’ liability insurance policies.

The LNB Bancorp board of directors was aware of and considered these interests, among other matters, in evaluating and recommending to the LNB Bancorp shareholders that they approve the Merger Agreement and the Merger.  The aggregate amount that each director and executive officer is expected to receive in connection with the

13

Table of Contents

Merger, and based on the assumptions therein, is set forth in “Proposal 1—Description of the Merger—Merger-Related Executive Compensation for LNB Bancorp’s Named Executive Officers and Directors” on page         .

Accounting Treatment of the Merger (page         )

The Merger will be accounted for using the acquisition method in accordance with U.S. generally accepted accounting principles.

Comparison of Rights of Shareholders (page         )

When the Merger is completed, LNB Bancorp shareholders who receive shares of Northwest Bancshares common stock will become Northwest Bancshares stockholders and their rights will be governed by Maryland law and by Northwest Bancshares’ articles of incorporation and bylaws.  The rights of LNB shareholders will change as a result of the Merger due to differences in Northwest Bancshares’ and LNB governing documents, as well as differences between Maryland and Ohio law.  See “Comparison of Rights of Shareholders” for a summary of the material differences between the respective rights of LNB Bancorp shareholders and Northwest Bancshares stockholders.

Dissenters’ Rights (page         )

Under Ohio law, LNB Bancorp shareholders who do not vote in favor of the Merger Proposal and deliver a written demand for payment for the fair cash value of their LNB Bancorp shares of common stock prior to the LNB Bancorp special meeting, will be entitled, if and when the Merger is completed, to receive the fair cash value of their shares of common stock. The right to make this demand is known as “dissenters’ rights.” LNB Bancorp shareholders’ right to receive the fair cash value of their shares of common stock, however, is contingent upon strict compliance with the procedures set forth in Section 1701.85 of the OGCL. An LNB Bancorp shareholder’s failure to vote against the adoption and approval of the Merger Agreement will not constitute a waiver of such shareholder’s dissenters’ rights, so long as such shareholder does not vote in favor of the Merger Agreement or return an unmarked proxy card.

For additional information regarding dissenters’ rights, see “Dissenters’ Rights” and the complete text of Section 1701.85 of the OGCL attached to this Proxy Statement/Prospectus as Appendix B. If LNB Bancorp shareholders should have any questions regarding dissenters’ rights, such shareholders should consult with their own legal advisers. See “Dissenters’ Rights” on page         .

Material Tax Consequences of the Merger (page         )

Northwest Bancshares and LNB Bancorp have each received a legal opinion that the Merger will qualify as a tax-free reorganization within the meaning of Section 368(a) of the Internal Revenue Code. However, the federal tax consequences of the Merger to a shareholder of LNB Bancorp will depend primarily on whether a shareholder exchanges his or her LNB Bancorp common stock solely for Northwest Bancshares common stock, solely for cash or for a combination of Northwest Bancshares common stock and cash. LNB Bancorp shareholders who exchange their shares solely for Northwest Bancshares common stock should not recognize a gain or loss except with respect to cash received in lieu of a fractional share of Northwest Bancshares common stock. LNB Bancorp shareholders who exchange their shares solely for cash should recognize a gain or loss on the exchange. LNB Bancorp shareholders who exchange their shares for a combination of Northwest Bancshares common stock and cash should recognize a gain, but not any loss, on the exchange. The actual federal income tax consequences to LNB Bancorp shareholders of electing to receive cash, Northwest Bancshares common stock or a combination of cash and stock will not be ascertainable at the time LNB Bancorp shareholders make their election because it will not be known at that time how, or to what extent, the allocation and proration procedures will apply.

This tax treatment may not apply to all LNB Bancorp shareholders. Determining the actual tax consequences of the Merger to LNB Bancorp shareholders can be complicated. LNB Bancorp shareholders

14

Table of Contents

should consult their own tax advisor for a full understanding of the Merger’s tax consequences that are particular to each shareholder.

To review the tax consequences of the Merger to LNB Bancorp shareholders in greater detail, please see the section “Proposal 1—Description of the Merger—Material Tax Consequences of the Merger.”

Risk Factors (page         )

You should consider all the information contained in or incorporated by reference into this Proxy Statement/Prospectus in deciding how to vote for the proposals presented in the Proxy Statement/Prospectus.  In particular, you should consider the factors described under “Risk Factors.”

15

Table of Contents

RISK FACTORS

In addition to the other information contained in or incorporated by reference into this Proxy Statement/Prospectus, including the matters addressed under the section titled “Caution About Forward-Looking Statements,” you should consider carefully the risk factors described below in deciding how to vote. You should also read and consider the risk factors associated with the business of Northwest Bancshares because these risk factors may affect the operations and financial results of the combined company.  These risk factors may be found in Northwest Bancshares’ Annual Report on Form 10-K for the year ended December 31, 2014.

Because the price of Northwest Bancshares common stock will fluctuate, LNB Bancorp shareholders cannot be certain of the market value of the merger consideration.

Upon completion of the Merger, each share of LNB Bancorp common stock will be converted into the right to receive 1.461 shares of Northwest Bancshares common stock. There will be no adjustment to the exchange ratio (except for adjustments to reflect the effect of any stock split, reverse stock split, stock dividend, recapitalization, reclassification or other similar transaction with respect to LNB Bancorp common stock), and LNB Bancorp does not have a right to terminate the Merger Agreement based upon changes in the market price of Northwest Bancshares common stock. Accordingly, the dollar value of Northwest Bancshares common stock that LNB Bancorp shareholders will receive upon completion of the Merger will depend upon the market value of Northwest Bancshares common stock at the time of completion of the Merger, which may be lower or higher than the closing price of Northwest Bancshares common stock on the last full trading day preceding public announcement that Northwest Bancshares and LNB Bancorp entered into the Merger Agreement, the last full trading day prior to the date this Proxy Statement/Prospectus was mailed or the date of the LNB Bancorp special meeting. The market values of Northwest Bancshares common stock and LNB Bancorp common stock have varied since Northwest Bancshares and LNB Bancorp entered into the Merger Agreement and will continue to vary in the future due to changes in the business, operations or prospects of Northwest Bancshares and LNB Bancorp, market assessments of the Merger, regulatory considerations, market and economic considerations, and other factors, most of which are beyond LNB Bancorp’s control. Accordingly, at the time of the LNB Bancorp special meeting, LNB Bancorp shareholders will not necessarily know or be able to calculate the value of the stock consideration they would be entitled to receive upon completion of the Merger.  You should obtain current market quotations for shares of Northwest Bancshares common stock and for shares of LNB Bancorp common stock. See “Market Price and Dividend Information” on page                for ranges of historic market prices of LNB Bancorp and Northwest Bancshares common stock.

LNB Bancorp will be subject to business uncertainties and contractual restrictions while the Merger is pending.

Uncertainty about the effect of the Merger on employees and customers may have an adverse effect on LNB Bancorp. These uncertainties may impair LNB Bancorp’s ability to attract, retain and motivate key personnel until the Merger is completed, and could cause customers and others who deal with LNB Bancorp to seek to change existing business relationships with LNB Bancorp. LNB Bancorp employee retention and recruitment may be particularly challenging prior to the effective time of the Merger, as employees and prospective employees may experience uncertainty about their future roles with the combined company.

The pursuit of the Merger and the preparation for the integration may place a significant burden on management and internal resources. Any significant diversion of management attention away from ongoing business and any difficulties encountered in the transition and integration process could affect LNB Bancorp’s financial results. In addition, the Merger Agreement requires that LNB Bancorp operate in the usual, regular and ordinary course of business and restricts LNB Bancorp from taking certain actions prior to the effective time of the Merger or termination of the Merger Agreement without Northwest Bancshares’ consent in writing. These restrictions may prevent LNB Bancorp from pursuing attractive business opportunities that may arise prior to the completion of the Merger.

16

Table of Contents

LNB Bancorp shareholders may receive a form of consideration different from what they elect.

The consideration to be received by LNB Bancorp shareholders in the Merger is subject to the requirement that 50% of the outstanding shares of LNB Bancorp common stock be exchanged for Northwest Bancshares common stock and the remaining 50% be exchanged for cash. The Merger Agreement contains proration and allocation methods to achieve this desired result. If you elect all cash and the available cash is oversubscribed, then you will receive a portion of the merger consideration in Northwest Bancshares common stock. If you elect all stock and the available stock is oversubscribed, then you will receive a portion of the merger consideration in cash.

Failure to complete the Merger could negatively impact the stock price and future business and financial results of LNB Bancorp.

LNB Bancorp has already incurred substantial expenses in connection with the Merger.  If the Merger is not completed, the ongoing business of LNB Bancorp may be adversely affected and LNB Bancorp will be subject to several risks, including the following:

·                                          If the Merger Agreement is terminated under specified circumstances, LNB Bancorp will be required to pay Northwest Bancshares a $7.3 million termination fee;

·                                          LNB Bancorp will be required to pay certain costs relating to the Merger, whether or not the Merger is completed, such as legal, accounting, financial advisory and printing fees;

·                                          under the Merger Agreement, LNB Bancorp is subject to certain restrictions on the conduct of its business prior to completing the Merger, which may adversely affect its operating results; and

·                                          matters relating to the Merger may require substantial commitments of time and resources by LNB Bancorp management, which could otherwise have been devoted to other opportunities that may have been beneficial to LNB Bancorp as an independent company.

In addition, if the Merger is not completed, LNB Bancorp may experience negative reactions from the financial markets and from its customers and employees. LNB Bancorp also could be subject to litigation related to any failure to complete the Merger or to enforcement proceedings to perform their respective obligations under the Merger Agreement. If the Merger is not completed, some or all of the risks described above may materialize and may materially affect LNB Bancorp’s business, financial results and stock price.

Northwest Bancshares may be unable to successfully integrate LNB Bancorp’s operations or otherwise realize the expected benefits from the Merger, which would adversely affect Northwest Bancshares’ results of operations and financial condition.

The Merger involves the integration of two companies that have previously operated independently. The difficulties of combining the operations of the two companies include:

·                                          integrating personnel with diverse business backgrounds;

·                                          converting customers to new systems;

·                                          combining different corporate cultures; and

·                                          retaining key employees.

The process of integrating operations could cause an interruption of, or loss of momentum in, the activities of the business and the loss of key personnel. The integration of the two companies will require the experience and expertise of certain key employees of LNB Bancorp who are expected to be retained by Northwest Bancshares.

17

Table of Contents

Northwest Bancshares may not be successful in retaining these employees for the time period necessary to successfully integrate LNB Bancorp’s operations with those of Northwest Bancshares. The diversion of management’s attention and any delay or difficulty encountered in connection with the Merger and the integration of the two companies’ operations could have an adverse effect on the business and results of operations of Northwest Bancshares following the Merger.

The success of the Merger will depend, in part, on Northwest Bancshares’ ability to realize the anticipated benefits and cost savings from combining the business of LNB Bancorp with Northwest Bancshares. If Northwest Bancshares is unable to successfully integrate LNB Bancorp, the anticipated benefits and cost savings of the Merger may not be realized fully or may take longer to realize than expected. For example, Northwest Bancshares may fail to realize the anticipated increase in earnings and cost savings anticipated to be derived from the Merger. In addition, as with regard to any merger, a significant decline in asset valuations or cash flows may also cause Northwest Bancshares not to realize expected benefits.

The termination fee and the restrictions on solicitation contained in the Merger Agreement may discourage other companies from trying to acquire LNB Bancorp.

Until the completion of the Merger, with some exceptions, LNB Bancorp is prohibited from soliciting, initiating, knowingly encouraging or participating in any discussion of or otherwise considering any inquiry or proposal that may lead to an acquisition proposal, such as a merger or other business combination transaction, with any person other than Northwest Bancshares. In addition, LNB Bancorp has agreed to pay a $7.3 million termination fee to Northwest Bancshares in specified circumstances. These provisions could discourage other companies that may have an interest in acquiring LNB Bancorp from considering or proposing such an acquisition even though those other companies might be willing to offer greater value to LNB Bancorp’s shareholders than Northwest Bancshares has offered in the Merger. The payment of the termination fee could also have a material adverse effect on LNB Bancorp’s financial condition.

Certain of LNB Bancorp’s officers and directors have interests that are different from, or in addition to, interests of LNB Bancorp shareholders generally.

You should be aware that the directors and officers of LNB Bancorp have interests in the Merger that are different from, or in addition to, the interests of LNB Bancorp shareholders generally. These include: one current LNB Bancorp board member joining the Northwest Bancshares board of directors upon completion of the Merger; all current LNB Bancorp board members will be appointed to a Northwest Bancshares advisory board to serve for an initial term of one year; payments of retention bonuses to certain executive officers of LNB Bancorp; continued employment that has been offered by Northwest Bank to LNB Bancorp’s President and Chief Executive Officer, as well as an acceleration of benefits in a supplemental executive retirement agreement between LNB Bancorp and its President and Chief Executive Officer upon a termination of employment within two years of the Merger; severance or other payments that certain officers may receive under existing employment or change-in-control agreements (assuming such agreements have not expired pursuant to their terms prior to the closing); the acceleration of unvested stock options and restricted stock awards; and provisions in the Merger Agreement relating to indemnification of directors and officers and insurance for directors and officers of LNB Bancorp for events occurring before the Merger. For a more detailed discussion of these interests, see “Proposal 1—Description of the Merger—Interests of Certain Persons in the Merger that are Different from Yours.”

LNB Bancorp shareholders will have a reduced ownership and voting interest after the Merger and will exercise less influence over management of the combined organization.

LNB Bancorp shareholders currently have the right to vote in the election of the LNB Bancorp board of directors and on various other matters affecting LNB Bancorp. Upon the completion of the Merger, each LNB Bancorp shareholder will become a stockholder of Northwest Bancshares with a percentage ownership of the combined organization that is significantly smaller than the shareholder’s percentage ownership of LNB Bancorp. It is expected that the former shareholders of LNB Bancorp as a group will receive shares in the Merger constituting approximately               % of the outstanding shares of Northwest Bancshares common stock immediately after the

18

Table of Contents

Merger, representing less than a majority of the ownership and voting power of Northwest Bancshares. As a result, LNB Bancorp shareholders will have significantly less influence on the management and policies of Northwest Bancshares than they now have on the management and policies of LNB Bancorp.

The shares of Northwest Bancshares common stock to be received by LNB Bancorp shareholders receiving the stock consideration as a result of the Merger will have different rights from shares of LNB Bancorp common stock.

Following completion of the Merger, LNB Bancorp shareholders who receive the stock consideration will no longer be shareholders of LNB Bancorp but will instead be stockholders of Northwest Bancshares. There will be important differences between the current rights of LNB Bancorp shareholders and the rights of Northwest Bancshares stockholders that may be important to LNB Bancorp shareholders. See “Comparison of Rights of Shareholders” beginning on page          for a discussion of the different rights associated with Northwest Bancshares common stock and LNB Bancorp common stock.

The fairness opinion received by LNB Bancorp’s board of directors from LNB Bancorp’s financial advisor does not reflect changes in circumstances subsequent to the date of the fairness opinion.

Sandler O’Neill, LNB Bancorp’s financial advisor in connection with the Merger, delivered to the board of directors of LNB Bancorp an opinion dated December 15, 2014. The opinion does not speak as of the time the Merger will be completed or any date other than the date of such opinion. The opinion does not reflect changes that may occur or may have occurred after the date of the opinion, including changes to the operations and prospects of Northwest Bancshares or LNB Bancorp, changes in general market and economic conditions or regulatory or other factors. Any such changes may materially alter or affect the relative values of Northwest Bancshares and LNB Bancorp.

There is no assurance when or even if the Merger will be completed.

Completion of the Merger is subject to satisfaction or waiver of a number of conditions. See “Proposal 1—Description of the Merger—Conditions to Completing the Merger” on page         . There can be no assurance that Northwest Bancshares and LNB Bancorp will be able to satisfy the closing conditions or that closing conditions beyond their control will be satisfied or waived.

Northwest Bancshares and LNB Bancorp can agree at any time to terminate the Merger Agreement, even if LNB Bancorp shareholders have already voted to approve the Merger Agreement. Northwest Bancshares and LNB Bancorp can also terminate the Merger Agreement under other specified circumstances.

Regulatory approvals may not be received, may take longer than expected or may impose conditions that are not presently anticipated.

Before the Merger may be completed, various approvals and consents must be obtained from regulatory entities. These regulators may impose conditions on the completion of the Merger or require changes to the terms of the Merger. Any such conditions or changes could have the effect of delaying completion of the Merger or imposing additional costs on or limiting the revenues of Northwest Bancshares following the Merger.

Either Northwest Bancshares or LNB Bancorp may terminate the Merger Agreement if the Merger has not been completed by September 30, 2015, unless the failure of the Merger to be completed has resulted from the failure of the party seeking to terminate the Merger Agreement to perform its obligations under the Merger Agreement, provided that the termination date will be automatically extended to December 31, 2015 if the inability to complete the Merger is solely due to a delay in receiving regulatory approvals.

19

Table of Contents

Goodwill incurred in the Merger may negatively affect Northwest Bancshares’ financial condition.

To the extent that the merger consideration, consisting of cash plus the number of shares of Northwest Bancshares common stock issued or to be issued in the Merger, exceeds the fair value of the net assets, including identifiable intangibles of LNB Bancorp, that amount will be reported as goodwill by Northwest Bancshares. In accordance with current accounting guidance, goodwill will not be amortized but will be evaluated for impairment annually. A failure to realize expected benefits of the Merger could adversely impact the carrying value of the goodwill recognized in the Merger, and in turn negatively affect Northwest Bancshares’ financial condition.

The price of Northwest Bancshares common stock might decrease after the Merger.

Upon completion of the Merger, holders of LNB Bancorp common stock who receive stock consideration will become stockholders of Northwest Bancshares. Northwest Bancshares common stock could decline in value after the Merger. For example, during the twelve-month period ending on [Record Date] (the most recent practicable date before the printing of this Proxy Statement/Prospectus), the closing price of Northwest Bancshares common stock varied from a low of $          to a high of $         and ended that period at $          . The market value of Northwest Bancshares common stock fluctuates based upon general market conditions, Northwest Bancshares’ business and prospects and other factors. Further, the market price of Northwest Bancshares common stock after the Merger may be affected by factors different from those currently affecting the common stock of Northwest Bancshares or LNB Bancorp. The businesses of LNB Bancorp and Northwest Bancshares differ and, accordingly, the results of operations of the combined company and the market price of the combined company’s shares of common stock may be affected by factors different from those currently affecting the independent results of operations and market prices of common stock of each of LNB Bancorp and Northwest Bancshares. For a discussion of the businesses of LNB Bancorp and Northwest Bancshares and of certain factors to consider in connection with those businesses, see the documents incorporated by reference in this Proxy Statement/Prospectus and referred to under “Where You Can Find More Information” beginning on page         .

CAUTION ABOUT FORWARD-LOOKING STATEMENTS

Certain statements contained in this document that are not historical facts may constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (referred to as the Securities Act), and Section 21E of the Securities Exchange Act of 1934, as amended (referred to as the Securities Exchange Act), and are intended to be covered by the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.  You can identify these statements from the use of the words “may,” “will,” “should,” “could,” “would,” “plan,” “potential,” “estimate,” “project,” “believe,” “intend,” “anticipate,” “expect,” “target” and similar expressions.

These forward-looking statements are subject to significant risks, assumptions and uncertainties, including among other things, changes in general economic and business conditions and the risks and other factors set forth in the “Risk Factors” section beginning on page         .

Additional factors that could cause the results of Northwest Bancshares or LNB Bancorp to differ materially from those described in the forward-looking statements can be found in the filings made by Northwest Bancshares and LNB Bancorp with the Securities and Exchange Commission, including the Northwest Bancshares Annual Report on Form 10-K for the fiscal year ended December 31, 2014 and the LNB Bancorp Annual Report on Form 10-K for the fiscal year ended December 31, 2014.

Because of these and other uncertainties, Northwest Bancshares’ and LNB Bancorp’s actual results, performance or achievements, or industry results, may be materially different from the results indicated by these forward-looking statements. In addition, Northwest Bancshares’ and LNB Bancorp’s past results of operations do not necessarily indicate Northwest Bancshares’ and LNB Bancorp’s combined future results. You should not place undue reliance on any of the forward-looking statements, which speak only as of the dates on which they were made. Neither Northwest Bancshares nor LNB Bancorp is undertaking an obligation to update these forward-looking statements, even though its situation may change in the future, except as required under the federal

20

Table of Contents

securities laws. All forward-looking statements contained in this document are qualified by these cautionary statements.

21

Table of Contents

SELECTED HISTORICAL FINANCIAL INFORMATION

The following tables show summarized historical financial data for Northwest Bancshares and LNB Bancorp. You should read this summary financial information in connection with Northwest Bancshares’ and LNB Bancorp’s historical financial information, which is incorporated by reference into this document.

SELECTED HISTORICAL FINANCIAL AND OTHER DATA OF NORTHWEST BANCSHARES, INC.

(1)                     Total included unallocated allowance for loan losses of $4.4 million, $4.7 million, $4.0 million, $4.4 million and $4.5 million for December 31, 2014, 2013, 2012, 2011 and 2010, respectively.

22

Table of Contents

(1)                     Represents net income divided by average assets.

(2)                     Represents net income divided by average equity.

(3)                     Represents average yield on interest-earning assets less average cost of interest-bearing liabilities (shown on a fully taxable equivalent basis).

(4)                     Represents net interest income as a percentage of average interest-earning assets (shown on a fully taxable equivalent basis).

23

Table of Contents

SELECTED HISTORICAL FINANCIAL AND OTHER DATA OF LNB BANCORP, INC.

(1)         Total net of allowance for loan losses of $17.4 million, $17.5 million, $17.6 million, $17.1 million and $16.1 million for December 31, 2014, 2013, 2012, 2011 and 2010, respectively.

24

Table of Contents

(1)         Represents net income divided by average assets.

(2)         Represents net income divided by average equity.

(3)         Represents average yield on interest-earning assets less average cost of interest-bearing liabilities (shown on a fully taxable equivalent basis).

(4)         Represents net interest income as a percentage of average interest-earning assets (shown on a fully taxable equivalent basis).

25

Table of Contents

SUMMARY SELECTED PRO FORMA CONDENSED COMBINED DATA

The following table shows selected financial information on a pro forma combined basis giving effect to the Merger (which is known as “pro forma” information) as if the Merger had become effective as of the date presented, in the case of the balance sheet information, and at the beginning of the period presented, in the case of the income statement information. The pro forma information reflects the acquisition method of accounting.

Northwest Bancshares anticipates that the Merger will provide the combined company with financial benefits that include reduced operating expenses and greater revenue. The pro forma information, while helpful in illustrating the financial characteristics of Northwest Bancshares following the Merger under one set of assumptions, does not reflect these benefits and, accordingly, does not attempt to predict or suggest future results. The pro forma information also does not necessarily reflect what the historical results of Northwest Bancshares would have been had its companies been combined during these periods.

The exchange ratio of 1.461 was used in preparing this selected pro forma information. You should read this summary pro forma information in conjunction with the information under “Pro Forma Financial Information” and with the historical information in this document on which it is based.

26

Table of Contents

UNAUDITED PRO FORMA COMBINED CONDENSED CONSOLIDATED FINANCIAL INFORMATION RELATING TO THE LNB BANCORP MERGER

The following unaudited pro forma combined condensed consolidated financial information has been prepared using the acquisition method of accounting, giving effect to the proposed Merger. The unaudited pro forma combined condensed consolidated statement of financial condition combines the historical financial information of Northwest Bancshares and LNB Bancorp as of December 31, 2014 and assumes that the Merger was completed on that date. The unaudited pro forma combined condensed consolidated statements of operations combine the historical financial information of Northwest Bancshares and LNB Bancorp and give effect to the Merger as if it had been completed as of January 1, 2014. The unaudited pro forma combined condensed consolidated financial information is presented for illustrative purposes only and is not necessarily indicative of the results of operations or financial condition had the Merger been completed on the dates described above, nor is it necessarily indicative of the results of operations in future periods or the future financial position of the combined entities. Certain reclassifications have been made to LNB Bancorp’s historical financial information in order to conform to Northwest Bancshares’ presentation of financial information.

The actual value of Northwest Bancshares common stock to be recorded as consideration in the Merger will be based on the closing price of Northwest Bancshares common stock at the time of the merger completion date. The proposed Merger is expected to be completed in the third quarter of 2015, but there can be no assurance that the Merger will be completed as anticipated. For purposes of the pro forma financial information, the fair value of Northwest Bancshares common stock to be issued in connection with the Merger was based on Northwest Bancshares’ closing price of $12.53 as of December 31, 2014.

The pro forma financial information includes estimated adjustments, including adjustments to record assets and liabilities of LNB Bancorp at its fair value, and represents the pro forma estimates by Northwest Bancshares based on available fair value information as of the date of the Merger Agreement.

The pro forma adjustments included herein are subject to change depending on changes in interest rates and the components of assets and liabilities, and as additional information becomes available and additional analyses are performed. The final allocation of the purchase price for the Merger will be determined after it is completed and after completion of thorough analyses to determine the fair value of LNB Bancorp’s tangible and identifiable intangible assets and liabilities as of the date the Merger is completed. Increases or decreases in the estimated fair values of the net assets as compared with the information shown in the unaudited pro forma combined condensed consolidated financial information may change the amount of the purchase price allocated to goodwill and other assets and liabilities and may impact Northwest Bancshares’ statement of operations due to adjustments in yield and/or amortization of the adjusted assets or liabilities. Any changes to LNB Bancorp’s shareholders’ equity, including results of operations from December 31, 2014 through the date the Merger is completed, will also change the purchase price allocation, which may include the recording of a lower or higher amount of goodwill. The final adjustments may be materially different from the unaudited pro forma adjustments presented herein.

Northwest Bancshares anticipates that the Merger will provide the combined company with financial benefits that include reduced operating expenses. These cost savings are not included in these pro forma statements and there can be no assurance that expected cost savings will be realized. The pro forma information, while helpful in illustrating the financial characteristics of the combined company under one set of assumptions, does not reflect the benefits of expected cost savings or opportunities to earn additional revenue and, accordingly, does not attempt to predict or suggest future results. It also does not necessarily reflect what the historical results of the combined company would have been had our companies been combined during the period.

The unaudited pro forma combined condensed consolidated financial information has been derived from and should be read in conjunction with the historical consolidated financial statements and the related notes of Northwest Bancshares and LNB Bancorp, which are incorporated in this Proxy Statement/Prospectus by reference.

27

Table of Contents

The unaudited pro forma stockholders’ equity and net income are qualified by the statements set forth under this caption and should not be considered indicative of the market value of Northwest Bancshares common stock or the actual or future results of operations of Northwest Bancshares for any period. Actual results may be materially different than the pro forma information presented.

28

Table of Contents

Unaudited Pro Forma Condensed Combined Consolidated Balance Sheet

as of December 31, 2014

(in thousands)