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Proxy Statement Pursuant to Section 14(a) of the Securities

Exchange Act of 1934 (Amendment No.     )



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¨Preliminary Proxy Statement
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¨Definitive Proxy Statement
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¨Soliciting Material Pursuant to §240.14a-12


SI Financial Group, Inc.

(Name of Registrant as Specified In Its Charter)



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.NNNNNNNNN NNNNNNNNNNNN+SI Financial Group, Inc.C 1234567890IMPORTANT ANNUAL MEETING INFORMATION000004NNNNNNENDORSEMENT_LINE______________ SACKPACK_____________MR A SAMPLE DESIGNATION (IF ANY) ADD 1ADD 2ADD 3ADD 4ADD 5ADD 6Vote by Internet• Go to www.envisionreports.com/SIFI• Or scan the QR code with your smartphone• Follow the steps outlined on the secure website SI Financial Group, Inc. Meeting Notice1234 5678 9012 345Important Notice Regarding the Availability of Proxy Materials for theSI Financial Group, Inc. Annual Meeting of Stockholders to be Held on May 9, 2018Under Securities and Exchange Commission rules, you are receiving this notice because the proxy materials for the company’s annual meeting of stockholders are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on and location of the annual meeting are on the reverse side. Your vote is important!This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The proxy statement and annual report to shareholders are available at:www.envisionreports.com/SIFIEasy Online Access — A Convenient Way to View Proxy Materials and VoteWhen you go online to view materials, you can also vote your shares.Step 1: Go to www.envisionreports.com/SIFI to view the materials.Step 2: Click on Cast Your Vote or Request Materials.Step 3: Follow the instructions on the screen to log in.Step 4: Make your selection as instructed on each screen to select delivery preferences and vote.When you go online, you can also help the environment by consenting to receive electronic delivery of future materials.Obtaining a Copy of the Proxy Materials – If you want to receive a copy of these documents, you must request one. There is no charge to you for requesting a copy. Please make your request for a copy as instructed on the reverse side on or before April 30, 2018 to facilitate timely delivery.2 N O TC O Y+ 02RK2A .





SI Financial Group, Inc. Meeting NoticeSI Financial Group, Inc. Annual Meeting of Stockholders will be held on May 9, 2018 at the Savings Institute Bank and Trust Company Financial Center, 579 North Windham Road, North Windham, Connecticut 06256, at 9:00 a.m. Local TimeProposals to be voted on at the annual meeting are listed below along with the Board of Directors’ recommendations.The Board of Directors recommends that you vote FOR each of the nominees and FOR Proposals 2 and 3:1.Election of Directors:Donna M. EvanRobert O. GillardDennis Pollack2.To ratify the selection of Wolf & Company, P.C. as our independent registered public accounting firm for the fiscal year ending December 31, 2018. 3.Advisory vote to approve the compensation of the company’s named executive officers as disclosed in the proxy statement. PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must vote online or request a paper copy of the proxy materials to receive a proxy card. If you wish to attend and vote at the annual meeting, please bring this notice with you.Here’s how to order a copy of the proxy materials and select a future delivery preference:Paper copies: Current and future paper delivery requests can be submitted via the telephone, Internet or email options below.Email copies: Current and future email delivery requests must be submitted via the Internet following the instructions below. If you request an email copy of current materials you will receive an email with a link to the materials.PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a set of proxy materials.gInternet – Go to www.envisionreports.com/SIFI. Click Cast Your Vote or Request Materials. Follow the instructions to log in and order a copy of the current meeting materials and submit your preference for email or paper delivery of future meeting materials. gTelephone – Call us free of charge at 1-866-641-4276 and follow the instructions to log in and order a paper copy of the materials by mail for the current meeting. You can also submit a preference to receive a paper copy for future meetings. gEmail – Send email to investorvote@computershare.com with “Proxy Materials SI Financial Group, Inc.” in the subject line. Include in the message your full name and address, plus the number located in the shaded bar on the reverse, and state in the email that you want a paper copy of current meeting materials. You can also state your preference to receive a paper copy for future meetings. To facilitate timely delivery, all requests for a paper copy of the proxy materials must be received by April 30, 2018. 02RK2A