Summary Prospectus by Investment Company (Form 497K)

State Street Balanced Index Fund Class K (SSBIX)

Summary Prospectus - April 30, 2026 

Before you invest, you may want to review the fund's prospectus, which contains more information about the fund and its risks. You may find the fund's prospectus and other information about the fund online at:

www.statestreet.com/im

You may also get this information at no cost by calling (800) 647-7327, by sending an e-mail request to [email protected], or by writing to the fund, c/o State Street Global Advisors Funds Distributors, LLC, One Iron Street, Boston, Massachusetts 02210. The fund's current prospectus and statement of additional information are incorporated by reference into this summary prospectus.

Investment Objective

With 60% of its assets, the State Street Balanced Index Fund (the "Fund") seeks to track the performance of a benchmark that measures the investment return of the overall U.S. stock market. With 40% of its assets, the Fund seeks to track the performance of a benchmark that measures the U.S. dollar denominated investment grade fixed-rate taxable bond market.

Fees and Expenses of the Fund

The tables below describe the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund ("Fund Shares"). You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.

Shareholder Fees (fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	None
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of the sale proceeds or the original offering price)	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 

Management Fee	0.05%
Distribution and/or Shareholder Service (12b-1) Fees	0.00%
Other Expenses1	0.09%
Acquired Fund Fees and Expenses2	0.01%
Total Annual Fund Operating Expenses	0.15%
Less Fee Waivers and/or Expense Reimbursements3	(0.10%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	0.05%

Total Annual Fund Operating Expenses (exclusive of non-recurring account fees, interest, taxes, and extraordinary expenses and distribution, shareholder servicing, and sub-transfer agency fees) exceed 0.05% of average daily net assets on an annual basis. This waiver and/or reimbursement may not be terminated prior to April 30, 2027 except with approval of the Fund's Board of Trustees.

Example:

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell or hold all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The calculation of costs for the one-year period takes into account the effect of any current contractual fee waivers and/or reimbursements; and the calculation of costs for the remaining periods takes such fee waivers and/or reimbursements into account only for the first year of each such period. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 year	3 years	5 years	10 years
$5	$38	$74	$182

Portfolio Turnover:

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund Shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 7% of the average value of its portfolio.

Principal Investment Strategies

The Fund uses a balanced approach to invest in a broad range of securities, including common stocks and fixed-income securities. Under normal circumstances, the Fund will invest at least 80% of its net assets (plus borrowings, if any) in securities comprising, in the aggregate, the indexes it seeks to track as part of its principal investment strategy, including securities that the Adviser determines have economic characteristics that are comparable to the economic characteristics of securities that comprise such indexes.

The Fund employs an indexing investment approach designed to track the performance of two benchmark indexes in a 60%/40% split between equity and fixed-income.

For the 60% equity allocation, the Fund seeks to track, before fees and expenses, the total return performance of the Dow Jones U.S. Total Stock Market Index, a member of the Dow Jones Total Stock Market Indices family, which is designed to measure all U.S. equity issues with readily available prices (the "Equity Index," and also an "Index"), over the long term.

For the 40% fixed income allocation, the Fund obtains its investment exposure by investing in a mutual fund that seeks to track, before fees and expenses, the total return performance of the Bloomberg U.S. Aggregate Bond Index, which is a benchmark that measures the performance of the U.S. dollar denominated investment grade fixed-rate taxable bond market (the "U.S. Aggregate Bond Index," and also an "Index"), over the long term. Fixed income securities comprising the U.S. Aggregate Bond Index may include Treasuries, government-related and corporate securities, mortgage-backed securities ("MBS") (agency fixed-rate pass-throughs), asset-backed securities ("ABS") and commercial mortgage-backed securities ("CMBS") (agency and non-agency).

The Fund's investments in fixed-income securities will be achieved primarily through a passive investment approach of investing all or substantially all of its assets allocated to fixed income investments in the State Street Aggregate Bond Index Portfolio (the "Aggregate Bond Index Portfolio" or the "Portfolio"), a mutual fund also advised by SSGA FM ("SSGA FM" or the "Adviser"). The Aggregate Bond Index Portfolio is an "index" fund that seeks to track, before fees and expenses, the total return performance of the U.S. Aggregate Bond Index over the long term.

In seeking to track the performance of the Equity Index and the U.S. Aggregate Bond Index, the Fund and the Portfolio, respectively, employ a sampling strategy, which means that the Fund/Portfolio will not typically purchase all of the securities represented in an Index. Instead, the Fund/Portfolio may purchase a subset of the securities in an Index, or securities SSGA FM considers to be comparable to securities in the applicable Index, in an effort to hold a portfolio of secu

rities with generally the same risk and return characteristics of such Index. The number of holdings in the Fund/Portfolio will be based on a number of factors, including asset size of the Fund/Portfolio. The Adviser generally expects the Fund/Portfolio to hold fewer than the total number of securities in the Equity Index and the U.S. Aggregate Bond Index, but reserves the right to hold as many securities as it believes necessary to achieve the Fund's/Portfolio's investment objective.

From time to time securities are added to or removed from an Index. The Fund/Portfolio may sell securities that are represented in the Equity Index and the U.S. Aggregate Bond Index, or purchase securities that are not yet represented in the applicable Index, prior to or after their removal or addition to such Index. The Fund/Portfolio may at times purchase or sell index futures contracts, or options on those futures, or engage in other transactions involving the use of derivatives, in lieu of investment directly in the securities making up an Index or to enhance the Fund's/Portfolio's replication of the applicable Index return. The Fund/Portfolio might do so, for example, in order to increase its investment exposure pending investment of cash in the securities comprising the Index. Alternatively, the Fund/Portfolio might use futures or options on futures to reduce its investment exposure in situations where it intends to sell a portion of the securities in its portfolio but the sale has not yet been completed. The Fund/Portfolio may also enter into other derivatives transactions, including the use of options or swap transactions, in lieu of investing directly in the securities making up an Index. The Fund/Portfolio may also, to the extent permitted by applicable law, invest in shares of other registered investment companies whose investment objectives and policies are similar to those of the Fund/Portfolio (including funds advised by the Adviser). The Fund's/Portfolio's return on its equity and fixed income allocations may not match the return of the Equity Index or the U.S. Aggregate Bond Index, respectively.

Principal Risks

The Fund is subject to the following principal risks. You could lose money by investing in the Fund. Certain risks relating to instruments and strategies used in the management of the Fund are placed first. The significance of any specific risk to an investment in the Fund will vary over time, depending on the composition of the Fund's portfolio, market conditions, and other factors. You should read all of the risk information presented below carefully, because any one or more of these risks may result in losses to the Fund. An investment in the Fund is subject to investment risks, including possible loss of principal, is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation ("FDIC") or any other government agency. The Fund may not achieve its investment objective. The Fund is not intended to be a complete investment program, but rather is intended for investment as part of a diversified investment portfolio. Investors should consult their own advisers as to the role of the Fund in their overall investment programs.

Market Risk: The Fund's investments are subject to changes in general economic conditions, general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors, including, but not limited to, economic growth or recession, changes in interest rates, inflation, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Local, regional or global events such as war, military conflicts, acts of terrorism, trade policy changes or disputes, the threat or actual imposition of tariffs, natural disasters, the spread of infectious illness or other public health issues, or other events could have a significant impact on the Fund and its investments.

Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time.

Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, changes in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments, or illiquidity in debt securities markets. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. During periods when interest rates are at low levels, the Fund's yield can be low, and the Fund may have a negative yield (i.e., it may lose money on an operating basis). To the

extent that interest rates fall, certain underlying obligations may be paid off substantially faster than originally anticipated. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities. High levels of inflation and/or a significantly changing interest rate environment can lead to heightened levels of volatility and reduced liquidity.

Mortgage-Related and Other Asset-Backed Securities Risk: Investments in mortgage-related and other asset-backed securities are subject to the risk of significant credit downgrades, illiquidity, and defaults to a greater extent than many other types of fixed-income investments. The liquidity of mortgage-related and asset-backed securities may change over time. During periods of falling interest rates, mortgage- and asset-backed securities may be called or prepaid, which may result in the Fund having to reinvest proceeds in other investments at a lower interest rate. During periods of rising interest rates, the average life of mortgage- and asset-backed securities may extend, which may lock in a below-market interest rate, increase the security's duration and interest rate sensitivity, and reduce the value of the security. Enforcing rights against the underlying assets or collateral may be difficult, and the underlying assets or collateral may be insufficient if the issuer defaults.

U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation ("Freddie Mac") and the Federal National Mortgage Association ("Fannie Mae") may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks.

Indexing Strategy/Index Tracking Risk: The Fund is managed with an indexing investment strategy, attempting to track the performance of an unmanaged index of securities, regardless of the current or projected performance of the Index or of the actual securities comprising the Index. This differs from an actively-managed fund, which typically seeks to outperform a benchmark index. As a result, the Fund's performance may be less favorable than that of a portfolio managed using an active investment strategy. The structure and composition of the Index will affect the performance, volatility, and risk of the Index and, consequently, the performance, volatility, and risk of the Fund. While the Adviser seeks to track the performance of the Index (i.e., achieve a high degree of correlation with the Index), the Fund's return may not match the return of the Index. The Fund incurs a number of operating expenses not applicable to the Index, and may incur costs in buying and selling securities. In addition, the Fund may not be fully invested at times, generally as a result of cash flows into or out of the Fund or reserves of cash held by the Fund to meet redemptions. The Adviser may attempt to replicate the Index return by investing in fewer than all of the securities in the Index, or in some securities not included in the Index, potentially increasing the risk of divergence between the Fund's return and that of the Index.

Derivatives Risk: Derivative transactions can create investment leverage and may have significant volatility. It is possible that a derivative transaction will result in a much greater loss than the principal amount invested, that changes in the value of a derivative transaction may not correlate perfectly with the underlying asset, and that the Fund may not be able to close out a derivative transaction at a favorable time or price. The counterparty to a derivatives contract may be unable or unwilling to make timely settlement payments, return the Fund's margin, or otherwise honor its obligations. A derivatives transaction may not behave in the manner anticipated by the Adviser or may not have the effect on the Fund anticipated by the Adviser.

Futures Contract Risks; Other Exchange-Traded Derivatives: The risk of loss relating to the use of futures contracts and other exchange-traded derivatives is potentially unlimited. There is no assurance that a liquid market on an exchange will exist for any particular futures contract or other exchange-traded derivative or at any particular time. In the event no such market exists for a particular derivative, it might not be possible to effect closing transactions, and the Fund will be unable to terminate its exposure to the derivative. If the Fund uses futures contracts or other exchange-traded derivatives for hedging purposes, there is a risk of imperfect correlation between movements in the prices of the derivatives and movements in the securities or index underlying the derivatives or movements

in the prices of the Fund's investments that are the subject of such hedge. Certain foreign futures contracts and other exchange-traded derivatives may be less liquid and more volatile than U.S. contracts. The Fund may be delayed or prevented from recovering margin or other amounts deposited with a futures commission merchant or futures clearinghouse.

Swaps Risk: A swap is a two-party contract that generally obligates the parties to exchange payments based on a specified reference security, basket of securities, security index or index component. Swaps can involve greater risks than direct investment in securities because swaps may be leveraged and are subject to counterparty risk (e.g., the risk of a counterparty's defaulting on the obligation or bankruptcy), credit risk and pricing risk (i.e., swaps may be difficult to value). It may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses.

Large Transactions Risk: To the extent a large proportion of the shares of the Fund are held by a small number of shareholders (or a single shareholder), including funds or accounts over which the Adviser has investment discretion, the Fund is subject to the risk that these shareholders will purchase or redeem Fund Shares in large amounts rapidly or unexpectedly, including as a result of an asset allocation decision made by the Adviser. In addition, a large number of shareholders collectively may purchase or redeem Fund shares in large amounts rapidly or unexpectedly (collectively, such transactions are referred to as "large shareholder transactions"). Large shareholder transactions could adversely affect the ability of the Fund to conduct its investment program.

Limited Track Record Risk: The Fund has a limited track record and there is no assurance that the Fund will grow quickly. When the Fund's size is small, the Fund may experience low trading volume, which could lead to wider bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange. Any resulting liquidation of the Fund could cause elevated transaction costs for the Fund and negative tax consequences for its shareholders.

Portfolio Turnover Risk: Frequent purchases and sales of portfolio securities may result in higher Fund expenses and may result in more significant distributions of short-term capital gains to investors, which are taxed to individuals as ordinary income.

Risk of Investment in Other Pools: If the Fund invests in another pooled investment vehicle (e.g., a mutual fund or exchange-traded fund), it is exposed to the risk that the other pool will not perform as expected and is exposed indirectly to all of the risks applicable to an investment in such other pool. The investment policies of the other pool may not be the same as those of the Fund; as a result, an investment in the other pool may be subject to additional or different risks than those to which the Fund is typically subject. The Fund bears its proportionate share of the fees and expenses of any pool in which it invests. The Adviser or an affiliate may serve as investment adviser to a pool in which the Fund may invest, leading to potential conflicts of interest. It is possible that other clients of the Adviser or its affiliates will purchase or sell interests in a pool sponsored or managed by the Adviser or its affiliates at prices and at times more favorable than those at which the Fund does so.

Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly.

Valuation Risk: Certain portfolio holdings may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including "fair valued" securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology.

Performance

The bar chart and table below provide some indication of the risks of investing in the Fund by illustrating the variability of the Fund's returns from year-to-year and by showing how the Fund's average annual returns for the periods indicated compared with that of (i) a broad measure of market performance and (ii) a composite index that consists of two different indexes. The bar chart shows how the Class K shares' returns have varied for each full calendar year shown. The Fund's past performance does not necessarily indicate how the Fund will perform in the future. Current performance information for the Fund is available toll free by calling (800) 997-7327 or by visiting our website at www.statestreet.com/im.

Annual Total Return (years ended 12/31)

  

	Returns	Quarter/Year
Highest Quarterly Return	7.07%	Q2 2025
Lowest Quarterly Return	-1.80%	Q1 2025

Average Annual Total Returns (for periods ended 12/31/25)

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. After-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").  

	One Year	Since Inception
		10/27/2023
Class K
Return Before Taxes	13.23 %	19.21 %
Return After Taxes on Distributions	12.10 %	18.43 %
Return After Taxes on Distributions and Sale of Fund Shares	8.19 %	14.74 %
S&P 500 Index (reflects no deduction for fees, expenses or taxes)	17.88 %	28.03 %
State Street Balanced Composite Index (reflects no deduction for fees, expenses or taxes)	13.30 %	19.53 %

The Fund will make updated performance information, including its current net asset value, available at the Fund's website: www.statestreet.com/im.

Investment Adviser

SSGA FM serves as the investment adviser to the Fund. The Adviser and certain other affiliates of State Street Corporation make up State Street Investment Management.

The professionals primarily responsible for the day-to-day management of the Fund are Leo Law and Seamus Quinn.

Leo Law, CFA, is a Principal of the Adviser and a Portfolio Manager in the Investment Solutions Group. He joined the Adviser in 2016.

Seamus Quinn, CFA, CAIA, is a Principal of the Adviser and a Portfolio Manager in the Investment Solutions Group. He joined the Adviser in 2012.

Purchase and Sale of Fund Shares

Purchase Minimums

The Fund's initial and subsequent investment minimums generally are as follows, although the Fund may reduce or waive the minimums in some cases. 

Class K
To establish an account	None
To add to an existing account	None

You may purchase or redeem Fund Shares on any day the Fund is open for business.

Written Requests and Wire Transfers. You may purchase or redeem Fund Shares by written request or wire transfer.

Written requests should be sent to:

By Mail:

State Street Funds
P.O. Box 219737
Kansas City, MO 64121-9737

By Overnight/Registered, Express, Certified Mail:

State Street Funds
801 Pennsylvania Avenue, Suite 219737
Kansas City, MO 64105-1307

By Intermediary:

If you wish to purchase or redeem Fund Shares through a broker, bank or other financial intermediary ("Financial Intermediary"), please contact that Financial Intermediary directly. Your Financial Intermediary may have different or additional requirements for opening an account and/or for the processing of purchase and redemption orders, or may be closed at times when the Fund is open. Financial Intermediaries may contact SS&C GIDS, Inc. at (877) 332-6207 or via email at [email protected] with questions.

Tax Information

The Fund's distributions are expected to be taxed as ordinary income, qualified dividend income and/or capital gains, unless you are investing through a tax-advantaged arrangement, such as a 401(k) plan or IRA. Any withdrawals made from such tax-advantaged arrangement may be taxable to you.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase Fund Shares through a broker-dealer or other Financial Intermediary (such as a bank), the Adviser or its affiliates may pay the Financial Intermediary for certain activities related to the Fund, including educational training programs, conferences, the development of technology platforms and reporting systems, or other services related to the sale or promotion of the Fund. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your Financial Intermediary's website for more information.