SIIT S&P 500 Index Fund

SIIT S&P 500 Index Fund

Investment Goal

Investment results that correspond to the aggregate price and dividend performance of the securities in the S&P 500 Index.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold Fund shares.

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	SIIT S&P 500 Index Fund Class A
Management Fees	0.03%
Distribution (12b-1) Fees	none
Other Expenses	0.08%
Total Annual Fund Operating Expenses	0.11%

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 redeem all of your 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.

Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
SIIT S&P 500 Index Fund | Class A | USD ($)	11	35	62	141

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 15% of the average value of its portfolio.

Principal Investment Strategies

The Fund invests substantially all of its assets (at least 80%) in securities listed in the S&P 500 Index, which is composed of approximately 500 leading U.S. publicly traded companies from a broad range of industries (mostly common stocks). The Fund's investment results are expected to correspond to the aggregate price and dividend performance of the S&P 500 Index (the Index) before the fees and expenses of the Fund. The Fund's investment performance will depend on the Fund's tracking of the Index and the performance of the Index. The Fund's ability to replicate the performance of the Index will depend to some extent on the size and timing of cash flows into and out of the Fund, as well as on the level of the Fund's expenses. The Fund may use futures contracts to obtain exposure to the equity market during high volume periods of investment into the Fund.

The Fund's sub-adviser (the Sub-Adviser) selects the Fund's securities under the general supervision of SEI Investments Management Corporation (SIMC or the Adviser), but the Sub-Adviser makes no attempt to "manage" the Fund in the traditional sense (i.e., by using economic, market or financial analyses). Instead, the Sub-Adviser generally will attempt to invest in securities composing the Index in approximately the same proportions as they are represented in the Index. It may not be possible or practicable to purchase all of the securities composing the Index or to hold them in the same weightings as they are represented in the Index. In those cases, the Sub-Adviser may employ a sampling or optimization technique to replicate the Index. In seeking to replicate the performance of the Index, the Fund may also invest in futures contracts, American depositary receipts (ADRs), exchange-traded funds (ETFs) and real estate investment trusts (REITs). The Fund may also invest a portion of its assets in securities of companies located in developed foreign countries and securities of small capitalization companies. The Sub-Adviser may, but is not required to, sell an investment if the merit of the investment has been substantially impaired by extraordinary events, such as fraud or a material adverse change in an issuer, or adverse financial conditions. The Fund's return may not match the return of the Index. The Index's market capitalization range and the composition of the Index are subject to change.

Principal Risks

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory and tax environments.

Derivatives Risk — The Fund's use of futures contracts is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk and liquidity risk are described below. Market risk is the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation are not yet fully known and may not be for some time. New regulation of derivatives may make them more costly, may limit their availability or may otherwise adversely affect their value or performance.

Equity Market Risk — The risk that stock prices will fall over short or extended periods of time.

Exchange-Traded Funds (ETFs) Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory and tax environments.

Investment Style Risk — The risk that the Fund's investment approach, which attempts to replicate the performance of the S&P 500 Index, may underperform other segments of the equity markets or the equity markets as a whole.

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.

REITs Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.

Small Capitalization Risk — Smaller capitalization companies in which the Fund invests may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization stocks may be more volatile than those of larger companies. Small capitalization stocks may be traded over-the-counter or listed on an exchange.

Tracking Error Risk — The risk that the Fund's performance may vary substantially from the performance of the benchmark index it tracks as a result of cash flows, Fund expenses, imperfect correlation between the Fund's and benchmark's investments and other factors.

Investing in the Fund involves risk, and there is no guarantee that the Fund will achieve its investment goal. You could lose money on your investment in the Fund, just as you could with other investments.

Performance Information

The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year for the past year, and by showing how the Fund's average annual returns for 1 year and since the Fund's inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1-800-DIAL-SEI.

Best Quarter: 5.21% (6/30/14)

Worst Quarter: 1.06% (9/31/14)

The Fund's total return from January 1, 2015 to June 30, 2015 was 1.27%.

Average Annual Total Returns (for the periods ended December 31, 2014)

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. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. In the event of negative performance, the Fund's returns after taxes on distributions and sale of Fund Shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund Shares. As a result, the Fund's returns after taxes on distributions and sale of Fund Shares may exceed the Fund's returns before taxes and/or returns after taxes on distributions.

Average Annual Returns - SIIT S&P 500 Index Fund	Label	Average Annual Returns, 1 Year	Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class A	Return Before Taxes	13.64%	15.51%		Dec. 18, 2013
After Taxes on Distributions | Class A	Return After Taxes on Distributions	13.06%	14.93%
After Taxes on Distributions and Sale of Fund Shares | Class A	Return After Taxes on Distributions and Sale of Fund Shares	8.06%	11.74%
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes)	S&P 500 Index Return (reflects no deduction for fees, expenses or taxes)	13.69%	13.69%	[1]	Dec. 31, 2013

[1] Index returns are shown from December 31, 2013.