THE OFFERING

Securities Offered

The securities offered in connection with this prospectus supplement are participation interests in the Savings Plan. Given the offering price of $8.00 per share and the value of the Savings Plan assets, the SI Financial Group Stock Fund Trustee may acquire up to 860,950 shares of SI Financial Group, Inc. common stock. Certain subscription rights and purchase limitations govern your investment in the SI Financial Group, Inc. Stock Fund in connection with the Stock offering. See “The Conversion and Offering — Subscription Offering and Subscription Rights” and “— Limitations on Purchases of Shares” in the prospectus attached to this prospectus supplement for further discussion of these subscription rights and purchase limitations.

The shares of common stock currently held in the Savings Plan will automatically be exchanged for shares of new SI Financial Group, Inc., a newly formed Maryland corporation, pursuant to an exchange ratio as more fully described in the prospectus attached to this prospectus supplement. See “The Conversion and Offering—Share Exchange Ratio for Current Shareholders.” Any new shares you purchase in the stock offering will be added to the shares of new SI Financial Group common stock that you receive in the exchange described above. All of these shares will be held in the SI Financial Group, Inc. Stock Fund.

This prospectus supplement contains information regarding the Savings Plan. The attached prospectus contains information regarding the stock offering and the financial condition, results of operations and business of Savings Institute. The address of the principal executive office of Savings Institute is 803 Main Street, Willimantic, Connecticut 06226. The telephone number of Savings Institute is 860-423-4581.

Election to Purchase Shares of New SI Financial Group Common Stock in the Stock Offering

In connection with the stock offering, you may direct the SI Financial Group Stock Fund Trustee to transfer all or part of the funds that represent your current beneficial interest in the assets of the Savings Plan (excluding your current investment in the SI Financial Group Stock Fund) to the SI Financial Group Stock Fund. The trustee will subscribe for the new SI Financial Group common stock in accordance with each participant’s direction. If there is not enough common stock in the stock offering to fill all subscriptions, the common stock will be apportioned and the SI Financial Group Stock Fund trustee may not be able to purchase all of the common stock you requested. In such a case, if you elect, the Trustee will purchase shares in the open market on your behalf, after the close of the stock offering, to fulfill your initial request. The Trustee may make such purchases at prices higher or lower than the $8.00 offering price.

Persons Who May Purchase Shares of New SI Financial Group Common Stock in the Stock Offering

All plan participants are eligible to direct a transfer of Savings Plan funds that are not currently invested in SI Financial Group common stock to the SI Financial Group Stock Fund. However, transfer directions are subject to subscription rights, purchase priorities and purchase limitations. If you are eligible to order shares in the subscription offering, your order will be filled in the following order of priority:

To the extent shares remain available after filling orders in the subscription offering, shares will be available in a community offering to natural persons residing in Hartford, Middlesex, New London, Tolland and Windham Counties in Connecticut, to our existing public shareholders and to the general public.

The limitation of the total amount of new SI Financial Group common stock that you may purchase in the Stock offering, as described in the prospectus (see “ The Conversion and Offering – Limitations on Purchases of Shares ”), will be calculated based on the aggregate amount that you subscribed for: (1) through your Savings Plan account; and (2) through

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your sources of funds outside of the Savings Plan by placing an order in the stock offering using a Stock Order Form. Whether you place an order through the Savings Plan, outside the plan or both, the number of shares of new SI Financial Group common stock, if any, that you receive will be determined based on the total number of subscriptions, your purchase priority and the allocation priorities set forth in the attached prospectus. If, as a result of the calculation, you are allocated insufficient shares to fill all of your orders, available shares will be allocated as described in “ The Conversion and Offering – Subscription Offering and Subscription Rights” in the prospectus. Available shares will be allocated between your Savings Plan order and your order outside of the Savings Plan. If you so elect, the shares of new SI Financial Group common stock you were unable to subscribe for through the Savings Plan will be purchased by the trustee on the open market immediately following the completion of the stock offering. If you elect to direct the trustee to purchase shares of new SI Financial Group common stock in the open market, you will not be able to direct the trustee as to the timing or price to be paid for the common stock. The trustee has sole discretion regarding the manner in which it will fill open market purchases.

Value of Participation Interests

As of July 31, 2010, the market value of the Savings Plan assets equaled approximately $6,887,600 (excluding those assets already invested in SI Financial Group common stock). The plan administrator has informed each participant of the value of his or her beneficial interest in the Savings Plan. The value of Savings Plan assets represents past contributions made to the Savings Plan on your behalf, plus or minus earnings or losses on the contributions, less previous withdrawals and loans.

Method of Directing Transfer

Included with this prospectus supplement is an investment form for you to use to direct a transfer of funds to the SI Financial Group Stock Fund (the “Investment Form”). If you wish to transfer all, or part, in multiples of not less than 5%, of your beneficial interest in the assets of the Savings Plan to the SI Financial Group Stock Fund, you should complete the Investment Form. If you do not wish to make such an election at this time, you do not need to take any action. The minimum investment in the SI Financial Group Stock Fund during the stock offering is $200.00.

Time for Directing Transfer

You must submit your direction to transfer amounts to the SI Financial Group Stock Fund in connection with the stock offering by the deadline of 5:00 p.m. on                 , 2010. You should return the Investment Form to Laurie Gervais in the Human Resources Department. Former Savings Institute employees who are participants in the Savings Plan should return their forms using the business reply envelope that has been provided with this prospectus supplement.

If you have any questions regarding the SI Financial Group Stock Fund or completing the Investment Form, please contact Laurie Gervais at (        )             -            .

Questions about the stock offering or about the prospectus should be directed to the Stock Information Center, toll-free at (        )             -            .

Irrevocability of Transfer Direction

Once you submit your Investment Form, you cannot change your direction to transfer amounts credited to your account in the Savings Plan to the SI Financial Group Stock Fund before the completion of the stock offering. Following the closing of the stock offering and the initial purchase of shares of SI Financial Group common stock through the SI Financial Group Stock Fund, you may change your investment directions, in accordance with the terms of the Savings Plan.

Purchase Price of New Shares of SI Financial Group Common Stock

The SI Financial Group Stock Fund Trustee will pay the same price for shares of new SI Financial Group common stock as all other persons who purchase shares of new SI Financial Group common stock in the stock offering. If there is not enough common stock in the Stock offering to fill all subscriptions, the common stock will be apportioned and the trustee may not be able to purchase all of the common stock you requested. If you elect, the SI Financial Group Stock Fund Trustee will purchase shares on your behalf after the close of the stock offering in the open market, to fulfill your initial request. The trustee may make such purchases at prices higher or lower than the $8.00 offering price.

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Nature of a Participant’s Interest in New Shares of SI Financial Group Common Stock

The trustee will hold SI Financial Group common stock in the name of the Savings Plan. The trustee will credit shares of common stock acquired at your direction to your account under the Savings Plan. Therefore, the investment designations of other Savings Plan participants should not affect earnings on your Savings Plan account.

Voting and Tender Rights of New Shares of SI Financial Group Common Stock

The SI Financial Group Stock Fund Trustee generally will exercise voting and tender rights attributable to all SI Financial Group common stock held by the SI Financial Group Stock Fund, as directed by participants with interests in the SI Financial Group Stock Fund. With respect to each matter as to which holders of SI Financial Group common stock have a right to vote, you will have voting instruction rights that reflect your proportionate interest in the SI Financial Group Stock Fund. The number of shares of SI Financial Group common stock held in the SI Financial Group Stock Fund voted for and against each matter will be proportionate to the number of voting instruction rights exercised. If there is a tender offer for SI Financial Group common stock, the Savings Plan allots each participant a number of tender instruction rights reflecting the participant’s proportionate interest in the SI Financial Group Stock Fund. The percentage of shares of SI Financial Group common stock held in the SI Financial Group Stock Fund that will be tendered will be the same as the percentage of the total number of tender instruction rights exercised in favor of the tender offer. The remaining shares of SI Financial Group common stock held in the SI Financial Group Stock Fund will not be tendered. The Savings Plan provides that participants will exercise their voting instruction rights and tender instruction rights on a confidential basis.

DESCRIPTION OF THE SAVINGS PLAN

Introduction

Savings Institute adopted the Savings Plan effective January 1, 1990. The Savings Plan was subsequently amended and restated in its entirety effective                     , 2010. Savings Institute intends for the Savings Plan to comply, in form and in operation, with all applicable provisions of the Internal Revenue Code and the Employee Retirement Income Security Act of 1974, as amended, or “ERISA.” Savings Institute may change the Savings Plan from time to time to ensure continued compliance with these laws. Savings Institute may also amend the Savings Plan from time to time to add, modify, or eliminate certain features of the plan, as it sees fit. Federal law provides you with various rights and protections as a participant in the Savings Plan, which is governed by ERISA. However, the Pension Benefit Guaranty Corporation does not guarantee your benefits under the Savings Plan.

Reference to Full Text of the Plan. The following portions of this prospectus supplement summarize the material provisions of the Savings Plan. Savings Institute qualifies this summary in its entirety by reference to the full text of the Savings Plan. You may obtain copies of the full Savings Plan document including any amendments to the plan and a summary plan description for the Savings Plan, by contacting Laurie Gervais in the Human Resources Department. You should carefully read the Savings Plan documents to understand your rights and obligations under the plan.

Eligibility and Participation

Eligible employees of Savings Institute who have attained age 21 and completed 90 days of employment with Savings Institute may begin to make pre-tax salary deferrals into the Savings Plan as of the first day of the month after they have satisfied the eligibility requirements.

As of July 31, 2010, 205 of the 252 eligible employees of Savings Institute participated in the Savings Plan.

Contributions Under the Savings Plan

Employee Pre-Tax Salary Deferrals. Subject to certain Internal Revenue Service limitations, the Savings Plan permits each participant to make pre-tax salary deferrals to the Savings Plan each payroll period of up to 100% of the participant’s pay. For purposes of the Savings Plan, a participant’s “pay” is defined as a participant’s base salary, commissions, overtime and bonuses. Participants may change their rate of pre-tax deferrals on a quarterly basis by completing a form and submitting it to the Human Resources Department.

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Savings Institute Matching Contributions. The Savings Plan provides that Savings Institute will make matching contributions on behalf of each participant equal to 50% of the participant’s deferral, up to a maximum of 6% of pay. Savings Institute makes matching contributions only for those participants who make pre-tax salary deferrals to the Savings Plan. If a participant stops making pre-tax salary deferrals to the Savings Plan, Savings Institute will cease its matching contributions on the participant’s behalf.

Savings Institute Discretionary Contributions. Savings Institute, in its sole discretion, may also make additional discretionary contributions, in amounts specified by the Board of Directors of Savings Institute. These discretionary contributions are allocated to each participant in the Savings Plan who is actively employed by Savings Institute on the last business day of the Plan Year and has completed 1,000 hours of service for Savings Institute during the Plan Year.

Rollover Contributions. Savings Institute allows employees who receive a distribution from a previous employer’s tax-qualified employee benefit plan to deposit that distribution into a Rollover Contribution account under the Savings Plan, provided the rollover contribution satisfies IRS requirements.

Limitations on Contributions

Limitation on Employee Salary Deferrals. Although the Savings Plan permits you to defer up to 100% of your pay, by law your total deferrals under the Savings Plan, together with similar plans, may not exceed $16,500 for 2010. Employees who are age 50 and over may also make additional, “catch-up” contributions to the plan, up to a maximum of $5,500 for 2010. The Internal Revenue Service periodically increases these limitations. A participant who exceeds these limitations must include any excess deferrals in gross income for federal income tax purposes in the year of deferral. In addition, the participant must pay federal income taxes on any excess deferrals when distributed by the Savings Plan to the participant, unless the plan distributes the excess deferrals and any related income no later than the first April 15th following the close of the taxable year in which the participant made the excess deferrals. Any income on excess deferrals distributed before such date is treated, for federal income tax purposes, as earned and received by the participant in the taxable year of the distribution.

Limitation on Annual Additions and Benefits. As required by the Internal Revenue Code, the Savings Plan provides that the total amount of contributions and forfeitures (annual additions) credited to a participant during any year under all defined contribution plans of Savings Institute (including the Savings Plan and the proposed Savings Institute Bank and Trust Company Employee Stock Ownership Plan) may not exceed the lesser of 100% of the participant’s annual compensation or $49,000 for 2010.

Limitation on Plan Contributions for Highly Compensated Employees. Special provisions of the Internal Revenue Code limit the amount of pre-tax and matching contributions that may be made to the Savings Plan in any year on behalf of highly compensated employees, in relation to the amount of pre-tax and matching contributions made by or on behalf of all other employees eligible to participate in the Savings Plan. If pre-tax and matching contributions exceed these limitations, the plan must adjust the contribution levels for highly compensated employees.

In general, a highly compensated employee includes any employee who (1) was a 5% owner of the sponsoring employer at any time during the year or the preceding year, or (2) had compensation for the preceding year in excess of $110,000 and, if the sponsoring employer so elects, was in the top 20% of employees by compensation for such year. The preceding dollar amount applies for 2010, and may be adjusted periodically by the Internal Revenue Service.

Top-Heavy Plan Requirements. If the Savings Plan is a Top-Heavy Plan for any calendar year, Savings Institute may be required to make certain contributions to the Savings Plan on behalf of non-key employees. In general, the Savings Plan will be treated as a “Top-Heavy Plan” for any calendar year if, as of the last day of the preceding calendar year, the aggregate balance of the accounts of Key Employees exceeds 60% of the aggregate balance of the accounts of all employees under the plan. A Key Employee is generally any employee who, at any time during the calendar year or any of the four preceding years, is:

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The foregoing dollar amounts are for 2010.

Savings Plan Investments

Assets in the Savings Plan Trust are currently invested in the funds specified below. The annual percentage return on these funds (net of fees) for the prior three years was:

Columbia Acorn Select Z Fund. This fund seeks long-term capital growth. The fund normally invests in companies with market capitalizations under $20 billion at the time of initial purchase. It may invest up to 33% of total assets in companies in developed markets (i.e., Japan, Canada and the U. K.) and emerging markets (i.e., China, Brazil and India).

Harbor Bond Institutional Fund. This fund seeks total return. The fund invests at least 80% of total assets in a diversified portfolio of bonds, which include all types of fixed-income securities. It primarily invests intermediate bonds with overall portfolio rated high quality. The fund may invest up to 30% of total assets in non-U.S. dollar-denominated securities. It also may invest up to 15% of total assets in securities of issuers based in countries with developing (or emerging markets) economies.

Vanguard Total Bond Market Index Fund. This fund seeks to track the performance of a broad, market-weighted bond index. The fund employs a “passive management,” or indexing investment approach designed to track the performance of the Barclays Capital U.S. Aggregate Float Adjusted Index. It invests by sampling the index. It invests at least 80% of assets in bonds held in the index. The fund maintains a dollar-weighted average maturity consistent with that of the index, ranging between 5 and 10 years.

Vanguard Inflation-Protected Securities Fund. This fund seeks to provide inflation protection and income consistent with investment in inflation-indexed securities. The fund invests at least 80% of assets in inflation-indexed bonds issued by the U.S. government. It may invest in bonds of any maturity, though the fund typically maintains a dollar-weighted average maturity of 7 to 20 years.

Harbor International Institutional Fund This fund seeks long-term total return, principally from growth of capital. The fund invests primarily (no less than 65% of total assets) in common and preferred stocks of foreign companies that have

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market capitalizations in excess of $1 billion, including those located in emerging market countries. It invests in a minimum of 10 countries throughout the world. The fund focuses on companies located in Europe, the Pacific Basin and emerging industrialized countries whose economies and political regimes appear more stable.

Davis New York Venture Y Fund. This fund seeks long-term growth of capital. The fund invests the majority of the assets in equity securities issued by large companies with market capitalizations of at least $10 billion. It has the flexibility to invest a limited portion of assets in companies of any size, to invest in companies whose shares may be subject to controversy, to invest in foreign securities, and to invest in non-equity securities.

Fidelity Capital Appreciation Fund. This fund seeks capital appreciation. The fund invests primarily in common stocks of domestic and foreign issuers. It may invest in either growth stocks or value stocks or both. The fund uses fundamental analysis of each issuer’s financial condition and industry position and market and economic conditions to select instruments.

Perkins Mid Cap Value T Fund. This fund seeks capital appreciation. The fund primarily invests in the common stocks of mid-sized companies whose stock prices the portfolio managers believe to be undervalued. It normally invests at least 80% of assets in equity securities of companies whose market capitalization falls, at the time of purchase, within the 12-month average of the capitalization range of the Russell Midcap Value index. The fund may invest in foreign equity and debt securities, which may include investments in emerging markets. It can also invest assets in derivatives.

Vanguard Small Cap Value Index Fund. This fund seeks to track the performance of a benchmark index that measures the investment return of small-capitalization value stocks. The fund employs a passive management investment approach designed to track the performance of the MSCI US Small Cap Value index, a broadly diversified index of value stocks of smaller U.S. companies. It attempts to replicate the target index by investing all, or substantially all, of assets in the stocks that make up the index, holding each stock in approximately the same proportion as its weighting in the index.

Vanguard Target Retirement Income Fund. The investment seeks current income and some capital appreciation. The fund invests in other Vanguard mutual funds according to an asset allocation designed for investors currently in retirement. It allocates approximately 70% of assets to bonds and money market instruments, and 30% of assets to stocks.

Vanguard Target Retirement 2010 Fund. This fund seeks to provide growth of capital and current income. The fund primarily invests in other Vanguard mutual funds according to an asset allocation strategy designed for investors planning to retire in or within a few years of 2010. The fund invests approximately 51% of assets in stocks and 49% in bonds.

Vanguard Target Retirement 2015 Fund. This fund seeks to provide growth of capital and current income. The fund primarily invests in other Vanguard mutual funds according to an asset allocation designed for investors planning to retire within a few years of 2015. It typically allocates approximately 61% of assets to stocks, and 39% to bonds.

Vanguard Target Retirement 2020 Fund. This fund seeks to provide growth of capital and current income. The fund primarily invests in other Vanguard mutual funds according to an asset allocation strategy designed for investors planning to retire in or within a few years of 2020. It allocates approximately 69% of assets to stocks and 31% to bonds.

Vanguard Target Retirement 2025 Fund. This fund seeks to provide growth of capital and current income. The fund primarily invests in other Vanguard mutual funds according to an asset allocation strategy designed for investors planning to retire within a few years of 2025. It allocates approximately 76% of assets to stocks and 24% to bonds.

Vanguard Target Retirement 2030 Fund. This fund seeks to provide growth of capital and current income. The fund primarily invests in other Vanguard mutual funds according to an asset allocation strategy designed for investors planning to retire in or within a few years of 2030. It allocates approximately 84% of assets to stocks and 16% to bonds.

Vanguard Target Retirement 2035 Fund. This fund seeks to provide growth of capital and current income. The fund primarily invests in other Vanguard mutual funds according to an asset allocation strategy designed for investors planning to retire within a few years of 2035. It allocates approximately 90% of assets to stocks and 10% to bonds.

Vanguard Target Retirement 2040 Fund. This fund seeks to provide growth of capital and current income. The fund primarily invests in other Vanguard mutual funds according to an asset allocation strategy designed for investors planning to retire in or within a few years of 2040. It allocates approximately 90% of assets to stocks and 10% to bonds.

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Vanguard Target Retirement 2045 Fund. This fund seeks to provide growth of capital and current income. The fund primarily invests in other Vanguard mutual funds according to an asset allocation strategy designed for investors planning to retire within a few years of 2045. It allocates approximately 90% of assets to stocks and 10% to bonds.

Vanguard Target Retirement 2050 Fund. This fund seeks to provide growth of capital and current income. The fund primarily invests in other Vanguard mutual funds according to an asset allocation strategy designed for investors planning to retire in or within a few years of 2050. It allocates approximately 90% of assets to stocks and 10% to bonds.

Federal US Treasury Cash Reinvestment Fund. This money market fund seeks current income consistent with stability of principal and liquidity by investing only in short-term U.S. Treasury securities.

Northern Trust Government Money Market Fund. The fund seeks to maximize current income to the extent consistent with the preservation of capital and maintenance of liquidity by investing exclusively in high quality money market instruments. This fund seeks to maintain a stable net asset value of $1.00 per share.

The SI Financial Group Stock Fund. This fund consists of investments in the common stock of SI Financial Group and a small amount of cash. Each participant’s proportionate undivided beneficial interest in the SI Financial Group Stock Fund is measured by units. The daily unit value is calculated by determining the market value of the common stock held and adding to that any cash held by the trustee. This total will be divided by the number of units outstanding to determine the unit value of the SI Financial Group Stock Fund.

If cash dividends are paid on SI Financial Group common stock, the Savings Plan trustee will, to the extent practicable, use the dividends held in the SI Financial Group Stock Fund to purchase shares of the common stock. Pending investment in the common stock, assets held in the SI Financial Group Stock Fund will be placed in short-term investments. The SI Financial Group Stock Fund is a single stock mutual fund and carries more investment risk than a typical mutual fund, which invests in more than one security.

Benefits Under the Savings Plan

Vesting. All participants are 100% vested in their pre-tax salary deferral and matching contribution account balances in the Savings Plan. This means that participants have a non-forfeitable right to these funds and any earnings on the funds at all times. Plan participants vest in their discretionary (profit sharing) contributions (if any) at a rate of 25% after the first two years of employment and 25% each additional year thereafter.

Withdrawals and Distributions From the Savings Plan

Withdrawals Before Termination of Employment. You may receive in-service distributions from the Savings Plan under limited circumstances in the form of hardship withdrawals and participant loans.

To qualify for a hardship withdrawal, you must have an immediate and substantial need to meet certain expenses and have no other reasonably available resources to meet the financial need. If you qualify for a hardship distribution, the trustee will make the distribution proportionately from the investment funds in which you have invested your account balances.

Participant loans are approved by the Savings Plan Administrator. If you qualify for a participant loan, the trustee will make a distribution proportionately from the investment funds in which you have invested your account balances. You may obtain information on the participant loan program from the Human Resources Department at Savings Institute.

Distribution Upon Retirement or Disability. The standard form of benefit upon retirement or disability is a lump sum payment. However, if the value of a participant’s accounts under the Savings Plan exceeds $1,000, the participant may elect to defer the lump sum payment until after retirement. However, the Internal Revenue Service requires that participants receive at least a portion of their plan accounts by the April 1 ^st of the calendar year following the calendar year in which they retire (or terminate service due to a disability) or the calendar year in which they reach age 70  ¹ / 2 . Participants may also choose to roll over all or a portion of their plan accounts to an Individual Retirement Account (IRA), or to another employer’s qualified plan, if the other employer’s plan permits rollover contributions.

Distribution Upon Death. A participant’s designated beneficiary will receive the full value of a participant’s accounts under the Savings Plan upon the participant’s death. If the participant did not make a valid election regarding the form of payment prior to death, the beneficiary will receive a lump sum payment as soon as administratively possible. If the

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participant made a valid payment election, or was otherwise scheduled to receive a deferred lump sum payment, the beneficiary will generally receive a lump sum payment on the date elected by the participant. Under certain circumstances, however, payment may be made on an earlier date.

Distribution Upon Termination for Any Other Reason. If your Savings Plan accounts total $1,000 or less, you will receive a lump sum payment as soon as administratively possible after your termination of employment. If the value of your Savings Plan accounts exceed $1,000, you will receive a lump sum payment on your normal retirement date. However, you may elect to receive the value of your vested Savings Plan accounts in a lump sum payment prior to your normal retirement date. You may also request that the trustee transfer the value of your accounts to an Individual Retirement Account (IRA) or to another employer’s qualified plan, if the other employer’s plan permits rollover contributions.

Nonalienation of Benefits. Except with respect to federal income tax withholding, and as provided for under a qualified domestic relations order, benefits payable under the Savings Plan will not be subject in any manner to anticipation, alienation, sale, transfer, assignment, pledge, encumbrance, charge, garnishment, execution, or levy of any kind, either voluntary or involuntary, and any attempt to anticipate, alienate, sell, transfer, assign, pledge, encumber, charge or otherwise dispose of any rights to benefits payable under the Savings Plan will be void.

Applicable federal tax law requires the Savings Plan to impose substantial restrictions on your right to withdraw amounts held under the plan before your termination of employment with Savings Institute. Federal law may also impose an excise tax on withdrawals from the Savings Plan before you attain 59  ¹ / 2 years of age, regardless of whether the withdrawal occurs during your employment with Savings Institute or after termination of employment.

ADMINISTRATION OF THE SAVINGS PLAN

Trustee

The trustee of the Savings Plan is the named fiduciary of the Savings Plan for ERISA. The board of directors of Savings Institute appoints the trustee to serve at its pleasure. The board of directors has appointed First Bankers Trust Services, Inc. as the trustee for the SI Financial Group Stock Fund. The Trust Department at Savings Institute is the trustee for all other assets in the Savings Plan.

The trustee receives, holds and invests the contributions to the Savings Plan in trust and distributes them to participants and beneficiaries in accordance with the terms of the Savings Plan and the directions of the plan administrator. The trustee is responsible for the investment of the trust assets, as directed by the participants.

Reports to Savings Plan Participants

The Plan trustee furnishes participants quarterly statements that show the balance in their accounts as of the statement date, contributions made to their accounts during that period and any additional adjustments required to reflect earnings or losses.

Plan Administrator

Savings Institute currently acts as plan administrator for the Savings Plan. The plan administrator handles the following administrative functions: interpreting the provisions of the plan, prescribing procedures for filing applications for benefits, preparing and distributing information explaining the plan, maintaining plan records, books of account and all other data necessary for the proper administration of the plan, preparing and filing all returns and reports required by the U.S. Department of Labor and the Internal Revenue Service and making all required disclosures to participants, beneficiaries and others under ERISA.

Amendment and Termination

Savings Institute expects to continue the Savings Plan indefinitely. Nevertheless, Savings Institute may terminate the Savings Plan at any time. If Savings Institute terminates the Savings Plan in whole or in part, all affected participants become fully vested in their accounts, regardless of other provisions of the Savings Plan. Savings Institute reserves the right to make, from time to time, changes which do not cause any part of the trust to be used for, or diverted to, any purpose other than the exclusive benefit of participants or their beneficiaries. Savings Institute may amend the plan, however, as necessary or desirable, in order to comply with ERISA or the Internal Revenue Code.

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Merger, Consolidation or Transfer

If the Savings Plan merges or consolidates with another plan or transfers the trust assets to another plan, and either the Savings Plan or the other plan is subsequently terminated, the Savings Plan requires that you receive a benefit immediately after the merger, consolidation or transfer that would equal or exceed the benefit you would have been entitled to receive immediately before the merger, consolidation or transfer, if the Savings Plan had terminated at that time.

Federal Income Tax Consequences

The following summarizes only briefly the material federal income tax aspects of the Savings Plan. You should not rely on this summary as a complete or definitive description of the material federal income tax consequences of the Savings Plan. Statutory provisions change, as do their interpretations, and their application may vary in individual circumstances. Finally, applicable state and local income tax laws may have different tax consequences than the federal income tax laws. Savings Plan Participants should consult a tax advisor with respect to any transaction involving the Savings Plan, including any distribution from the Savings Plan.

As a “tax-qualified retirement plan,” the Internal Revenue Code affords the Savings Plan certain tax advantages, including the following:

Savings Institute administers the Savings Plan to comply in operation with the requirements of the Internal Revenue Code as of the applicable effective date of any change in the law. If Savings Institute should receive an adverse determination letter from the IRS regarding the Savings Plan’s tax exempt status, all participants would generally recognize income equal to their vested interests in the Savings Plan, the participants would not be permitted to transfer amounts distributed from the Savings Plan to an Individual Retirement Account or to another qualified retirement plan, and Savings Institute would be denied certain tax deductions taken in connection with the Savings Plan.

Lump Sum Distribution. A distribution from the Savings Plan to a participant or the beneficiary of a participant qualifies as a lump sum distribution if it is made within one taxable year, on account of the participant’s death, disability or separation from service, or after the participant attains age 59  ¹ / 2 ; and consists of the balance credited to the participant under this plan and all other profit sharing plans, if any, maintained by Savings Institute. The portion of any lump sum distribution included in taxable income for federal income tax purposes consists of the entire amount of the lump sum distribution, less the amount of after-tax contributions, if any, made to any other profit-sharing plans maintained by Savings Institute, if the distribution includes those amounts.

SI Financial Group Common Stock Included in Lump Sum Distribution. If a lump sum distribution includes SI Financial Group common stock, the distribution generally is taxed in the manner described above. The total taxable amount is reduced, however, by the amount of any net unrealized appreciation on SI Financial Group common stock; that is, the excess of the value of SI Financial Group common stock at the time of the distribution over the cost or other basis of the securities to the trust. The tax basis of SI Financial Group common stock, for computing gain or loss on a subsequent sale, equals the value of SI Financial Group common stock at the time of distribution, less the amount of net unrealized appreciation. Any gain on a subsequent sale or other taxable disposition of SI Financial Group common stock, to the extent of the net unrealized appreciation at the time of distribution, is long-term capital gain, regardless of how long you hold the SI Financial Group common stock, or the “holding period.” Any gain on a subsequent sale or other taxable disposition of SI Financial Group common stock that exceeds the amount of net unrealized appreciation upon distribution is considered long-term capital gain, regardless of the holding period. The recipient of a distribution may elect to include the amount of any net unrealized appreciation in the total taxable amount of the distribution, to the extent allowed under IRS regulations.

We have provided you with a brief description of the material federal income tax aspects of the Savings Plan that are generally applicable under the Internal Revenue Code. We do not intend this description to be a complete or definitive description of the federal income tax consequences of participating in or receiving distributions from the Savings Plan. Accordingly, you should consult a tax advisor concerning the federal, state and local tax consequences of participating in and receiving distributions from the Savings Plan.

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Restrictions on Resale

Any “affiliate” of SI Financial Group under Rules 144 and 405 of the Securities Act of 1933, as amended, who receives a distribution of common stock under the Savings Plan, may re-offer or resell such shares only under a registration statement filed under the Securities Act of 1933, as amended, assuming the availability of a registration statement, or under Rule 144 or some other exemption from these registration requirements. An “affiliate” of Savings Institute is someone who directly or indirectly, through one or more intermediaries, controls, is controlled by, or is under common control with, Savings Institute. Generally, a director, principal officer or major shareholder of a corporation is deemed to be an “affiliate” of that corporation.

Any person who may be an “affiliate” of Savings Institute may wish to consult with counsel before transferring any common stock they own. In addition, participants should consult with counsel regarding the applicability to them of Section 16 of the Securities Exchange Act of 1934, as amended, which may restrict the sale of SI Financial Group common stock acquired under the Savings Plan or other sales of SI Financial Group common stock.

Persons who are not deemed to be “affiliates” of Savings Institute at the time of resale may resell freely any shares of SI Financial Group common stock distributed to them under the Savings Plan, either publicly or privately, without regard to the registration and prospectus delivery requirements of the Securities Act of 1933, as amended, or compliance with the restrictions and conditions contained in the exemptions available under federal law. A person deemed an “affiliate” of Savings Institute at the time of a proposed resale may publicly resell common stock only under a “re-offer” prospectus or in accordance with the restrictions and conditions contained in Rule 144 of the Securities Act of 1933, as amended, or some other exemption from registration, and may not use this prospectus in connection with any such resale. In general, Rule 144 restricts the amount of common stock which an affiliate may publicly resell in any three-month period to the greater of one percent of SI Financial Group common stock then outstanding or the average weekly trading volume reported on the Nasdaq Stock Market during the four calendar weeks before the sale. Affiliates may sell only through brokers without solicitation and only at a time when SI Financial Group is current in filing all required reports under the Securities Exchange Act of 1934, as amended.

SEC Reporting and Short-Swing Profit Liability

Section 16 of the Securities Exchange Act of 1934, as amended, imposes reporting and liability requirements on officers, directors and persons who beneficially own more than ten percent of public companies such as SI Financial Group Section 16(a) of the Securities Exchange Act of 1934, as amended, requires the filing of reports of beneficial ownership. Within ten days of becoming a person required to file reports under Section 16(a), such person must file a Form 3 reporting initial beneficial ownership with the Securities and Exchange Commission. Such persons must also report periodically certain changes in beneficial ownership involving the allocation or reallocation of assets held in their Savings Plan accounts, either on a Form 4 within two days after a transaction, or annually on a Form 5 within 45 days after the close of a company’s fiscal year.

In addition to the reporting requirements described above, Section 16(b) of the Securities Exchange Act of 1934, as amended, provides for the recovery by SI Financial Group of profits realized from the purchase and sale or sale and purchase of its common stock within any six-month period by any officer, director or person who beneficially owns more than ten percent of the common stock.

The SEC has adopted rules that exempt many transactions involving the Savings Plan from the “short-swing” profit recovery provisions of Section 16(b). The exemptions generally involve restrictions upon the timing of elections to buy or sell employer securities for the accounts of any officer, director or person who beneficially owns more than ten percent of the common stock.

Except for distributions of the common stock due to death, disability, retirement, termination of employment or under a qualified domestic relations order, persons who are subject to Section 16(b) may be required, under limited circumstances involving the purchase of common stock within six months of the distribution, to hold the shares of common stock distributed from the Savings Plan for six months after the distribution date.

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LEGAL OPINION

The validity of the issuance of the common stock of SI Financial Group will be passed upon by Kilpatrick Stockton LLP, Washington, D.C. Kilpatrick Stockton LLP acted as special counsel for SI Financial Group in connection with the stock offering.

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PROSPECTUS

(Proposed holding company for Savings Institute Bank and Trust Company)

Up to 7,546,875 Shares of Common Stock

(Subject to increase to 8,678,906 shares)

SI Financial Group, Inc., a newly formed Maryland corporation, is offering common stock for sale in connection with the conversion of SI Bancorp, MHC from the mutual to the stock form of organization.

We are offering up to 7,546,875 shares of common stock for sale on a best efforts basis, subject to certain conditions. We must sell a minimum of 5,578,125 shares to complete the offering. All shares are offered at a price of $8.00 per share. Purchasers will not pay a commission to purchase shares of common stock in the offering. The amount of capital being raised is based on an independent appraisal of new SI Financial Group. Most of the terms of this offering are required by regulations of the Office of Thrift Supervision. If, as a result of regulatory considerations, demand for the shares or changes in financial market conditions, the independent appraiser determines that our market value has increased, we may sell up to 8,678,906 shares without giving you further notice or the opportunity to change or cancel your order. SI Financial Group, Inc.’s common stock is currently listed on the Nasdaq Global Market under the symbol “SIFI.” We expect that new SI Financial Group’s common stock will trade on the Nasdaq Global Market under the trading symbol SIFID for a period of 20 trading days after the completion of the offering. Thereafter, the trading symbol will be SIFI.

The shares we are offering represent the 61.9% ownership interest in SI Financial Group, a federal corporation, currently owned by SI Bancorp, MHC. The remaining 38.1% interest in SI Financial Group currently owned by public shareholders will be exchanged for shares of common stock of new SI Financial Group. Each share of SI Financial Group owned by public shareholders will be exchanged for between 0.7655 and 1.0357 shares of common stock of new SI Financial Group (subject to increase to 1.1910 if we sell 8,678,906 shares in the offering) so that SI Financial Group’s existing public shareholders will own approximately the same percentage of new SI Financial Group common stock as they owned of SI Financial Group’s common stock immediately before the conversion. We also intend to make a $500,000 cash contribution to SI Financial Group Foundation, Inc., our charitable foundation, in connection with the conversion. The present SI Financial Group and SI Bancorp, MHC will cease to exist upon completion of the conversion and offering.

We are offering the shares of common stock in a “subscription offering” to eligible depositors of Savings Institute Bank and Trust Company. Shares of common stock not purchased in the subscription offering may be offered for sale to the general public in a “community offering,” with a preference given to our communities and existing shareholders of SI Financial Group. We also may offer for sale shares of common stock not purchased in the subscription offering or community offering through a “syndicated community offering” managed by Stifel, Nicolaus & Company, Incorporated. We retain the right to accept or reject, in part or in whole, any order received in the community offering or the syndicated community offering. Stifel, Nicolaus & Company, Incorporated is not required to purchase any shares of common stock that are being offered for sale.

The minimum order is 25 shares. The subscription offering will end at 2:00 p.m., Eastern time, on [Date 1], 2010. We expect that the community offering, if held, will terminate at the same time, although it may continue without notice to you until [Date 2], 2010 or longer if the Office of Thrift Supervision approves a later date. No single extension may exceed 90 days and the offering must be completed by [Date 3], 2012. Once submitted, orders are irrevocable unless the offering is terminated or is extended beyond [Date 2], 2010, or the number of shares of common stock to be sold is increased to more than 8,678,906 shares or decreased to less than 5,578,125 shares. If we extend the offering beyond [Date 2], 2010, all subscribers will be notified and given the opportunity to confirm, change or cancel their orders. If you do not respond to this notice, we will promptly return your funds, with interest calculated at Savings Institute’s passbook savings rate or cancel your deposit account withdrawal authorization. If we intend to sell fewer than 5,578,125 shares or more than 8,678,906 shares, we will promptly return all funds and set a new offering range. All subscribers will be notified and given the opportunity to place a new order. Funds received before the completion of the subscription and community offerings will be held in a segregated account at Savings Institute and will earn interest at Savings Institute’s passbook savings rate, which is currently 0.20% per annum.

This investment involves a degree of risk, including the possible loss of principal.

Please read “Risk Factors” beginning on page 17.