485BPOS

As filed with the Securities and Exchange Commission on February 15, 2013

File Nos. 333-37177

811-08403

SECURITIES AND EXCHANGE COMMISSION

Washington,   D.C.   20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933	¨
Pre-Effective Amendment No.	¨
Post-Effective Amendment No. 26	x

and/or

REGISTRATION STATEMENT

UNDER

THE INVESTMENT COMPANY ACT OF 1940

Amendment No. 27 x

ALLIANCEBERNSTEIN INSTITUTIONAL

FUNDS, INC.

(Exact Name of Registrant as Specified in Charter)

1345 Avenue of the Americas,

New York, New York 10105

(Address of Principal Executive Office) (Zip Code)

Registrant’s Telephone Number, including Area Code:

(800) 221-5672

Emilie D. Wrapp

AllianceBernstein L.P.

1345 Avenue of the Americas

New York, New York 10105

(Name and address of agent for service)

Copies of communications to:

Kathleen K. Clarke

Seward & Kissel LLP

901 K Street, N.W.

Suite 800

Washington, DC 20001

It is proposed that this filing will become effective (check appropriate box)

¨ immediately upon filing pursuant to paragraph (b)

x on February 15, 2013 pursuant to paragraph (b)

¨ 60 days after filing pursuant to paragraph (a)(1)

¨ on (date) pursuant to paragraph (a)(1)

¨ 75 days after filing pursuant to paragraph (a)(2)

¨ on (date) pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

¨ This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

This Post-Effective Amendment No. 26 relates to the Class I shares of the AllianceBernstein Global Real Estate Investment Fund II. No information contained in the Registrant’s Registration Statement relating to the Class II shares of the AllianceBernstein Global Real Estate Investment Fund II is amended or superseded hereby.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant certifies that it meets all of the requirements for effectiveness to this amendment to its Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Post-Effective Amendment No. 26 to its Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City and State of New York, on the 15^th day of February, 2013.

ALLIANCEBERNSTEIN INSTITUTIONAL FUNDS, INC.
By:	Robert M. Keith*
	Robert M. Keith President

Pursuant to the requirements of the Securities Act of 1933, as amended this Post-Effective Amendment No. 26 to the Registration Statement has been signed below by the following persons in the capacities and on the dates indicated:

	Signature	Title	Date
1)	Principal Executive Officer:
	Robert M.Keith* Robert M. Keith	President and Chief Executive Officer	February 15, 2013
2)	Principal Financial and Accounting Officer:
	/s/    Joseph J. Mantineo Joseph J. Mantineo	Treasurer and Chief Financial Officer	February 15, 2013
3)	Directors:
	John H. Dobkin* Michael J. Downey* William H. Foulk, Jr.* D. James Guzy* Nancy P. Jacklin* Robert M. Keith* Garry L. Moody* Marshall C. Turner, Jr.* Earl D. Weiner*
*By:	/s/    Stephen J. Laffey Stephen J. Laffey (Attorney-in-fact)		February 15, 2013

Index to Exhibits

Exhibit No.	Description of Exhibits
EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-101.CALC	XBRL Taxonomy Extension Calculation Linkbase
EX-101.DEF	XBRL Taxonomy Extension Definition Linkbase
EX-101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	ALLIANCEBERNSTEIN INSTITUTIONAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Jan. 31, 2013
Document Creation Date	dei_DocumentCreationDate	Jan. 30, 2013

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	ALLIANCEBERNSTEIN INSTITUTIONAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Jan. 31, 2013
AllianceBernstein Global Real Estate Investment Fund II
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	ALLIANCE BERNSTEIN GLOBAL REAL ESTATE INVESTMENT FUND II
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund's investment objective is total return from long-term growth of capital and income.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	SHAREHOLDER FEES (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys or 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 transaction costs, which are not reflected in the Annual Fund Operating Expenses or in the Examples, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 101% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	101.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	EXAMPLES
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The Examples are intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. They assume that you invest $10,000 in the Fund for the time periods indicated. They also assume that your investment has a 5% return each year and that the Fund's operating expenses stay the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Fund invests at least 80% of its net assets in the equity securities of real estate investment trusts, or REITs, and other real estate industry companies, such as real estate operating companies. The Fund invests in real estate companies that the Adviser believes have strong property fundamentals and management teams. The Fund seeks to invest in real estate companies whose underlying portfolios are diversified geographically and by property type. The Fund invests in U.S. and non-U.S. issuers. Under normal circumstances, the Fund invests significantly (at least 40%--unless market conditions are not deemed favorable by the Adviser) in securities of non-U.S. companies. In addition, the Fund invests, under normal circumstances, in the equity securities of companies located in at least three countries. The Fund's investment policies emphasize investment in companies determined by the Adviser to be undervalued relative to their peers, using a fundamental value approach. In selecting real estate equity securities, the Adviser's research and investment process seeks to identify globally those companies where the magnitude and growth of cash flow streams have not been appropriately reflected in the price of the security. These securities may trade at a more attractive valuation than others that may have similar overall fundamentals. The Adviser's fundamental research efforts are focused on forecasting the short- and long-term normalized cash generation capability of real estate companies by isolating supply and demand for property types in local markets, determining the replacement value of properties, assessing future development opportunities, and normalizing capital structures of real estate companies. The Fund may invest in mortgage-backed securities, which are securities that directly or indirectly represent participations in, or are collateralized by and payable from, mortgage loans secured by real property. These securities include mortgage pass-through certificates, real estate mortgage investment conduit certificates, or REMICs, and collateralized mortgage obligations, or CMOs. The Fund may also invest in short-term investment grade debt securities and other fixed-income securities. Currencies can have a dramatic impact on equity return, significantly adding to returns in some years and greatly diminishing them in others. The Adviser evaluates currency and equity positions separately and may seek to hedge the currency exposure resulting from securities positions when it finds the currency exposure unattractive. To hedge a portion of its currency risk, the Fund may from time to time invest in currency-related derivatives, including forward currency exchange contracts, futures, options on futures, swaps and options. The Adviser also may seek investment opportunities by taking long or short positions in currencies through the use of currency-related derivatives. The Fund invests in equity securities that include common stock, shares of beneficial interest of REITs, and securities with common stock characteristics, such as preferred stock or convertible securities ("real estate equity securities"). The Fund may enter into forward commitments and standby commitment agreements. The Fund may enter into other derivatives transactions, such as options, futures, forwards, and swaps. The Fund may use options strategies involving the purchase and/or writing of various combinations of call and/or put options, including on individual securities and stock indexes, futures (including futures on individual securities and stock indexes) or exchange-traded funds ("ETFs"). These transactions may be used, for example, to earn extra income, to adjust exposure to individual securities or markets, or to protect all or a portion of the Fund's portfolio from a decline in value, sometimes within certain ranges. The Fund may, at times, invest in ETFs in lieu of making direct investments in equity securities. ETFs may provide more efficient and economical exposure to the type of companies and geographic locations in which the Fund seeks to invest than direct investments.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	Under normal circumstances, the Fund invests at least 80% of its net assets in the equity securities of real estate investment trusts, or REITs, and other real estate industry companies, such as real estate operating companies.
Risk [Heading]	rr_RiskHeading	PRINCIPAL RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	MARKET RISK: The value of the Fund's assets will fluctuate as the stock or bond market fluctuates. The value of its investments may decline, sometimes rapidly and unpredictably, simply because of economic changes or other events that affect large portions of the market. INTEREST RATE RISK: Changes in interest rates will affect the value of investments in fixed-income securities. When interest rates rise, the value of investments in fixed-income securities tend to fall and this decrease in value may not be offset by higher income from new investments. Interest rate risk is generally greater for fixed-income securities with longer maturities or durations. CREDIT RISK: An issuer or guarantor of a fixed-income security, or the counterparty to a derivatives or other contract, may be unable or unwilling to make timely payments of interest or principal, or to otherwise honor its obligations. The issuer or guarantor may default, causing a loss of the full principal amount of a security. The degree of risk for a particular security may be reflected in its credit rating. There is the possibility that the credit rating of a fixed-income security may be downgraded after purchase, which may adversely affect the value of the security. Investments in fixed-income securities with lower ratings tend to have a higher probability that an issuer will default or fail to meet its payment obligations. REAL ESTATE RISK: The Fund's investments in real estate securities have many of the same risks as direct ownership of real estate, including the risk that the value of real estate could decline due to a variety of factors affecting the real estate market generally. Investments in REITs may have additional risks. REITs are dependent on the capability of their managers, may have limited diversification, and could be significantly affected by changes in taxes. FOREIGN (NON-U.S.) RISK: Investment in securities of non-U.S. issuers may involve more risk than those of U.S. issuers. These securities may fluctuate more widely in price and may be less liquid due to adverse market, economic, political, regulatory or other factors. CURRENCY RISK: Fluctuations in currency exchange rates may negatively affect the value of the Fund's investments or reduce its returns. PREPAYMENT RISK: The value of mortgage-related or other asset-backed securities may be particularly sensitive to changes in prevailing interest rates. Early payments of principal on some mortgage-related securities may occur during periods of falling mortgage interest rates and expose the Fund to a lower rate of return upon reinvestment of principal. Early payments associated with mortgage-related securities cause these securities to experience significantly greater price and yield volatility than is experienced by traditional fixed-income securities. During periods of rising interest rates, a reduction in prepayments may increase the effective life of mortgage-related securities, subjecting them to greater risk of decline in market value in response to rising interest rates. If the life of a mortgage-related security is inaccurately predicted, the Fund may not be able to realize the rate of return it expected. DERIVATIVES RISK: Investments in derivatives may be illiquid, difficult to price, and leveraged so that small changes may produce disproportionate losses for the Fund, and may be subject to counterparty risk to a greater degree than more traditional investments. LEVERAGE RISK: When the Fund borrows money or otherwise leverages its portfolio, it may be more volatile because leverage tends to exaggerate the effect of any increase or decrease in the value of the Fund's investments. The Fund may create leverage through the use of reverse repurchase agreements or forward commitments, or by borrowing money. MANAGEMENT RISK: The Fund is subject to management risk because it is an actively managed investment fund. The Adviser will apply its investment techniques and risk analyses in making investment decisions for the Fund, but there is no guarantee that its techniques will produce the desired results. As with all investments, you may lose money by investing in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, you may lose money by investing in the Fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	BAR CHART AND PERFORMANCE INFORMATION
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and performance information provide an indication of the historical risk of an investment in the Fund by showing: how the Fund's performance changed from year to year over ten years; and how the Fund's average annual returns for one, five and ten years compare to those of a broad-based securities market index. You may obtain updated performance information on the Fund's website at www.AllianceBernstein.com (click on "Individuals-U.S." then "Products & Performance"). The Fund's past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	how the Fund's performance changed from year to year over ten years; and how the Fund's average annual returns for one, five and ten years compare to those of a broad-based securities market index.
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.AllianceBernstein.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	BAR CHART
Bar Chart Narrative [Text Block]	rr_BarChartNarrativeTextBlock	The annual returns in the bar chart are for the Fund's Class I shares.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the Fund's: BEST QUARTER WAS UP 28.98%, 2ND QUARTER, 2009; AND WORST QUARTER WAS DOWN -30.30%, 4TH QUARTER, 2008.
Performance Table Heading	rr_PerformanceTableHeading	PERFORMANCE TABLE AVERAGE ANNUAL TOTAL RETURNS (For the periods ended December 31, 2012)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	Are an estimate, which is based on the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes;
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Are not relevant to investors who hold Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.
AllianceBernstein Global Real Estate Investment Fund II | Class I
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Maximum Sales Charge (Load) Imposed on Reinvested Dividends	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Exchange Fee	rr_ExchangeFee	none
Management Fees	rr_ManagementFeesOverAssets	0.55%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.01%
Other Expenses	rr_Component2OtherExpensesOverAssets	0.07%
Total Other Expenses	rr_OtherExpensesOverAssets	0.08%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.63%
After 1 Year	rr_ExpenseExampleYear01	64
After 3 Years	rr_ExpenseExampleYear03	202
After 5 Years	rr_ExpenseExampleYear05	351
After 10 Years	rr_ExpenseExampleYear10	786
03	rr_AnnualReturn2003	39.20%
04	rr_AnnualReturn2004	35.61%
05	rr_AnnualReturn2005	11.59%
06	rr_AnnualReturn2006	36.11%
07	rr_AnnualReturn2007	(7.37%)
08	rr_AnnualReturn2008	(45.00%)
09	rr_AnnualReturn2009	36.03%
10	rr_AnnualReturn2010	18.88%
11	rr_AnnualReturn2011	(6.92%)
12	rr_AnnualReturn2012	30.46%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	BEST QUARTER
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	28.98%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	WORST QUARTER
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(30.30%)
1 YEAR	rr_AverageAnnualReturnYear01	30.46%	[1]
5 YEARS	rr_AverageAnnualReturnYear05	1.55%	[1]
10 YEARS	rr_AverageAnnualReturnYear10	11.03%	[1]
AllianceBernstein Global Real Estate Investment Fund II | Return After Taxes on Distributions | Class I
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	27.71%	[1]
5 YEARS	rr_AverageAnnualReturnYear05	0.05%	[1]
10 YEARS	rr_AverageAnnualReturnYear10	8.95%	[1]
AllianceBernstein Global Real Estate Investment Fund II | Return After Taxes on Distributions and Sale of Fund Shares | Class I
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	19.89%	[1]
5 YEARS	rr_AverageAnnualReturnYear05	0.44%	[1]
10 YEARS	rr_AverageAnnualReturnYear10	8.87%	[1]
AllianceBernstein Global Real Estate Investment Fund II | S&P 500 Index
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	16.00%	[2]
5 YEARS	rr_AverageAnnualReturnYear05	1.66%	[2]
10 YEARS	rr_AverageAnnualReturnYear10	7.10%	[2]
AllianceBernstein Global Real Estate Investment Fund II | MSCI World Index (net) (reflects no deduction for fees, expenses or taxes except the reinvestment of dividends net of non-U.S. withholding taxes)
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	15.83%	[3]
5 YEARS	rr_AverageAnnualReturnYear05	(1.18%)	[3]
10 YEARS	rr_AverageAnnualReturnYear10	7.51%	[3]
AllianceBernstein Global Real Estate Investment Fund II | FTSE NAREIT Equity REIT Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	28.65%	[3]
5 YEARS	rr_AverageAnnualReturnYear05	1.07%	[3]
10 YEARS	rr_AverageAnnualReturnYear10	12.08%	[3]
AllianceBernstein Global Real Estate Investment Fund II | FTSE EPRA/NAREIT Developed Real Estate Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	19.70%	[3]
5 YEARS	rr_AverageAnnualReturnYear05	5.74%	[3]
10 YEARS	rr_AverageAnnualReturnYear10	11.78%	[3]

[1] After-tax Returns: -Are an estimate, which is based on the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes; actual after-tax returns depend on an individual investor's tax situation and are likely to differ from those shown; and -Are not relevant to investors who hold Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

[2] The S&P 500 Index provides broad-based information about the performance of 500 U.S. large-cap companies and is regarded as a gauge of the U.S. equities markets.

[3] The MSCI World Index (net) provides broad-based information about the performance of global markets. The FTSE NAREIT Equity REIT Index and the FTSE EPRA/NAREIT Developed Real Estate Index provide more information about the performance of REITs in the U.S. and global markets, respectively.

XML

AllianceBernstein Global Real Estate Investment Fund II

ALLIANCE BERNSTEIN GLOBAL REAL ESTATE INVESTMENT FUND II

INVESTMENT OBJECTIVE

The Fund's investment objective is total return from long-term growth of capital and income.

FEES AND EXPENSES OF THE FUND

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

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees (USD $)	AllianceBernstein Global Real Estate Investment Fund II Class I
Maximum Sales Charge (Load) Imposed on Purchases	none
Maximum Deferred Sales Charge (Load)	none
Maximum Sales Charge (Load) Imposed on Reinvested Dividends	none
Exchange Fee	none

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

Annual Fund Operating Expenses	AllianceBernstein Global Real Estate Investment Fund II Class I
Management Fees	0.55%
Distribution and/or Service (12b-1) Fees	none
Other Expenses: Transfer Agent	0.01%
Other Expenses	0.07%
Total Other Expenses	0.08%
Total Annual Fund Operating Expenses	0.63%

EXAMPLES

The Examples are intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. They assume that you invest $10,000 in the Fund for the time periods indicated. They also assume that your investment has a 5% return each year and that the Fund's operating expenses stay the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	AllianceBernstein Global Real Estate Investment Fund II Class I
After 1 Year	64
After 3 Years	202
After 5 Years	351
After 10 Years	786

PORTFOLIO TURNOVER

The Fund pays transaction costs, such as commissions, when it buys or 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 transaction costs, which are not reflected in the Annual Fund Operating Expenses or in the Examples, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 101% of the average value of its portfolio.

PRINCIPAL STRATEGIES

Under normal circumstances, the Fund invests at least 80% of its net assets in the equity securities of real estate investment trusts, or REITs, and other real estate industry companies, such as real estate operating companies. The Fund invests in real estate companies that the Adviser believes have strong property fundamentals and management teams. The Fund seeks to invest in real estate companies whose underlying portfolios are diversified geographically and by property type.

The Fund invests in U.S. and non-U.S. issuers. Under normal circumstances, the Fund invests significantly (at least 40%--unless market conditions are not deemed favorable by the Adviser) in securities of non-U.S. companies. In addition, the Fund invests, under normal circumstances, in the equity securities of companies located in at least three countries.

The Fund's investment policies emphasize investment in companies determined by the Adviser to be undervalued relative to their peers, using a fundamental value approach. In selecting real estate equity securities, the Adviser's research and investment process seeks to identify globally those companies where the magnitude and growth of cash flow streams have not been appropriately reflected in the price of the security. These securities may trade at a more attractive valuation than others that may have similar overall fundamentals. The Adviser's fundamental research efforts are focused on forecasting the short- and long-term normalized cash generation capability of real estate companies by isolating supply and demand for property types in local markets, determining the replacement value of properties, assessing future development opportunities, and normalizing capital structures of real estate companies.

The Fund may invest in mortgage-backed securities, which are securities that directly or indirectly represent participations in, or are collateralized by and payable from, mortgage loans secured by real property. These securities include mortgage pass-through certificates, real estate mortgage investment conduit certificates, or REMICs, and collateralized mortgage obligations, or CMOs. The Fund may also invest in short-term investment grade debt securities and other fixed-income securities.

Currencies can have a dramatic impact on equity return, significantly adding to returns in some years and greatly diminishing them in others. The Adviser evaluates currency and equity positions separately and may seek to hedge the currency exposure resulting from securities positions when it finds the currency exposure unattractive. To hedge a portion of its currency risk, the Fund may from time to time invest in currency-related derivatives, including forward currency exchange contracts, futures, options on futures, swaps and options. The Adviser also may seek investment opportunities by taking long or short positions in currencies through the use of currency-related derivatives.

The Fund invests in equity securities that include common stock, shares of beneficial interest of REITs, and securities with common stock characteristics, such as preferred stock or convertible securities ("real estate equity securities"). The Fund may enter into forward commitments and standby commitment agreements. The Fund may enter into other derivatives transactions, such as options, futures, forwards, and swaps. The Fund may use options strategies involving the purchase and/or writing of various combinations of call and/or put options, including on individual securities and stock indexes, futures (including futures on individual securities and stock indexes) or exchange-traded funds ("ETFs"). These transactions may be used, for example, to earn extra income, to adjust exposure to individual securities or markets, or to protect all or a portion of the Fund's portfolio from a decline in value, sometimes within certain ranges.

The Fund may, at times, invest in ETFs in lieu of making direct investments in equity securities. ETFs may provide more efficient and economical exposure to the type of companies and geographic locations in which the Fund seeks to invest than direct investments.

PRINCIPAL RISKS

• MARKET RISK: The value of the Fund's assets will fluctuate as the stock or bond market fluctuates. The value of its investments may decline, sometimes rapidly and unpredictably, simply because of economic changes or other events that affect large portions of the market.

• INTEREST RATE RISK: Changes in interest rates will affect the value of investments in fixed-income securities. When interest rates rise, the value of investments in fixed-income securities tend to fall and this decrease in value may not be offset by higher income from new investments. Interest rate risk is generally greater for fixed-income securities with longer maturities or durations.

• CREDIT RISK: An issuer or guarantor of a fixed-income security, or the counterparty to a derivatives or other contract, may be unable or unwilling to make timely payments of interest or principal, or to otherwise honor its obligations. The issuer or guarantor may default, causing a loss of the full principal amount of a security. The degree of risk for a particular security may be reflected in its credit rating. There is the possibility that the credit rating of a fixed-income security may be downgraded after purchase, which may adversely affect the value of the security. Investments in fixed-income securities with lower ratings tend to have a higher probability that an issuer will default or fail to meet its payment obligations.

• REAL ESTATE RISK: The Fund's investments in real estate securities have many of the same risks as direct ownership of real estate, including the risk that the value of real estate could decline due to a variety of factors affecting the real estate market generally. Investments in REITs may have additional risks. REITs are dependent on the capability of their managers, may have limited diversification, and could be significantly affected by changes in taxes.

• FOREIGN (NON-U.S.) RISK: Investment in securities of non-U.S. issuers may involve more risk than those of U.S. issuers. These securities may fluctuate more widely in price and may be less liquid due to adverse market, economic, political, regulatory or other factors.

• CURRENCY RISK: Fluctuations in currency exchange rates may negatively affect the value of the Fund's investments or reduce its returns.

• PREPAYMENT RISK: The value of mortgage-related or other asset-backed securities may be particularly sensitive to changes in prevailing interest rates. Early payments of principal on some mortgage-related securities may occur during periods of falling mortgage interest rates and expose the Fund to a lower rate of return upon reinvestment of principal. Early payments associated with mortgage-related securities cause these securities to experience significantly greater price and yield volatility than is experienced by traditional fixed-income securities. During periods of rising interest rates, a reduction in prepayments may increase the effective life of mortgage-related securities, subjecting them to greater risk of decline in market value in response to rising interest rates. If the life of a mortgage-related security is inaccurately predicted, the Fund may not be able to realize the rate of return it expected.

• DERIVATIVES RISK: Investments in derivatives may be illiquid, difficult to price, and leveraged so that small changes may produce disproportionate losses for the Fund, and may be subject to counterparty risk to a greater degree than more traditional investments.

• LEVERAGE RISK: When the Fund borrows money or otherwise leverages its portfolio, it may be more volatile because leverage tends to exaggerate the effect of any increase or decrease in the value of the Fund's investments. The Fund may create leverage through the use of reverse repurchase agreements or forward commitments, or by borrowing money.

• MANAGEMENT RISK: The Fund is subject to management risk because it is an actively managed investment fund. The Adviser will apply its investment techniques and risk analyses in making investment decisions for the Fund, but there is no guarantee that its techniques will produce the desired results.

As with all investments, you may lose money by investing in the Fund.

BAR CHART AND PERFORMANCE INFORMATION

The bar chart and performance information provide an indication of the historical risk of an investment in the Fund by showing:

• how the Fund's performance changed from year to year over ten years; and

• how the Fund's average annual returns for one, five and ten years compare to those of a broad-based securities market index.

You may obtain updated performance information on the Fund's website at www.AllianceBernstein.com (click on "Individuals-U.S." then "Products & Performance").

The Fund's past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.

BAR CHART

The annual returns in the bar chart are for the Fund's Class I shares.

During the period shown in the bar chart, the Fund's:

BEST QUARTER WAS UP 28.98%, 2ND QUARTER, 2009; AND WORST QUARTER WAS DOWN -30.30%, 4TH QUARTER, 2008.

PERFORMANCE TABLE
AVERAGE ANNUAL TOTAL RETURNS

(For the periods ended December 31, 2012)

Average Annual Total Returns AllianceBernstein Global Real Estate Investment Fund II		1 YEAR	5 YEARS	10 YEARS
Class I	[1]	30.46%	1.55%	11.03%
Class I Return After Taxes on Distributions	[1]	27.71%	0.05%	8.95%
Class I Return After Taxes on Distributions and Sale of Fund Shares	[1]	19.89%	0.44%	8.87%
S&P 500 Index	[2]	16.00%	1.66%	7.10%
MSCI World Index (net) (reflects no deduction for fees, expenses or taxes except the reinvestment of dividends net of non-U.S. withholding taxes)	[3]	15.83%	(1.18%)	7.51%
FTSE NAREIT Equity REIT Index (reflects no deduction for fees, expenses, or taxes)	[3]	28.65%	1.07%	12.08%
FTSE EPRA/NAREIT Developed Real Estate Index (reflects no deduction for fees, expenses, or taxes)	[3]	19.70%	5.74%	11.78%

[1] After-tax Returns: -Are an estimate, which is based on the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes; actual after-tax returns depend on an individual investor's tax situation and are likely to differ from those shown; and -Are not relevant to investors who hold Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

[2] The S&P 500 Index provides broad-based information about the performance of 500 U.S. large-cap companies and is regarded as a gauge of the U.S. equities markets.

[3] The MSCI World Index (net) provides broad-based information about the performance of global markets. The FTSE NAREIT Equity REIT Index and the FTSE EPRA/NAREIT Developed Real Estate Index provide more information about the performance of REITs in the U.S. and global markets, respectively.

XML

Document and Entity Information	12 Months Ended
	Jan. 31, 2013
Risk/Return:
Document Type	485BPOS
Document Period End Date	Oct. 31, 2012
Registrant Name	ALLIANCEBERNSTEIN INSTITUTIONAL FUNDS INC
Central Index Key	0001018592
Amendment Flag	false
Document Creation Date	Jan. 30, 2013
Document Effective Date	Jan. 31, 2013
Prospectus Date	Jan. 31, 2013