UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED

MANAGEMENT INVESTMENT COMPANIES

Investment Company Act File Number:    811-09631                                         

Cohen & Steers Institutional Realty Shares, Inc.

(Exact name of registrant as specified in charter)

280 Park Avenue, New York, NY 10017

(Address of principal executive offices) (Zip code)

Dana A. DeVivo

Cohen & Steers Capital Management, Inc.

280 Park Avenue

New York, New York 10017

(Name and address of agent for service)

Registrant’s telephone number, including area code:     (212) 832-3232                                         

Date of fiscal year end:     December 31                                         

Date of reporting period:    December 31, 2019                                        

Item 1. Reports to Stockholders.

COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

To Our Shareholders:

We would like to share with you our report for the year ended December 31, 2019. The total returns for Cohen & Steers Institutional Realty Shares, Inc. (the Fund) and its comparative benchmarks were:

	Six Months Ended December 31, 2019			Year Ended December 31, 2019
Cohen & Steers Institutional Realty Shares		9.74	%		33.01	%
Linked Benchmarka		7.87	%		27.74	%
S&P 500 Indexa		10.92	%		31.49	%

The performance data quoted represent past performance. Past performance is no guarantee of future results. The investment return and the principal value of an investment will fluctuate and shares, if redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data quoted. Current total returns of the Fund can be obtained by visiting our website at cohenandsteers.com. The Fund’s returns assume the reinvestment of all dividends and distributions at net asset value (NAV). Fund performance reflects fee waivers and/or expense reimbursements, without which the performance would have been lower. Index performance does not reflect the deduction of any fees, taxes or expenses. An investor cannot invest directly in an index. Performance figures for periods shorter than one year are not annualized.

Please note that distributions paid by the Fund to shareholders are subject to recharacterization for tax purposes and are taxable up to the amount of the Fund’s investment company taxable income and net realized gains. Distributions in excess of the Fund’s investment company taxable income and net realized gains are a return of capital distributed from the Fund’s assets.

Market Review

U.S. REITs enjoyed exceptional returns in 2019, supported by generally healthy property fundamentals and declining interest rates. Prospects of slowing economic growth prompted the U.S. Federal Reserve to respond forcefully with rate cuts and other easing measures, driving meaningful gains in the equity market. A resilient economy—marked by a 50-year low in unemployment and 111 consecutive months of job growth—resulted in healthy demand for most property types, coinciding with peaking supply in many sectors. Companies also benefited from easy access to capital at historically low rates, providing a healthy environment for cash flow growth.

^a  The Linked Benchmark is represented by the performance of the FTSE Nareit Equity REITs Index through March 31, 2019 and the FTSE Nareit All Equity REITs Index thereafter. The FTSE Nareit Equity REITs Index contains all tax-qualified real estate investment trusts (REITs) except timber and infrastructure REITs with more than 50% of total assets in qualifying real estate assets other than mortgages secured by real property that also meet minimum size and liquidity criteria. The FTSE Nareit All Equity REITs Index contains all tax-qualified REITs with more than 50% of total assets in qualifying real estate assets other than mortgages secured by real property that also meet minimum size and liquidity criteria. The S&P 500 Index is an unmanaged index of 500 large-capitalization stocks that is frequently used as a general measure of U.S. stock market performance.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

Fund Performance

The Fund had a strong total return in 2019 and outperformed its linked benchmark. The growing influence of e-commerce on real estate was a key driver of absolute and relative performance. Data centers and towers continued to benefit from rapid growth in data usage as well as increased capital spending on 5G infrastructure. The Fund’s stock selection and overweight allocations to these sectors contributed to relative performance during the year. Industrial landlords were another top-performing sector; supply struggled to keep pace with the demand for well-located distribution centers, as Amazon and other online retailers expanded supply-chain logistics capabilities. In our view, the earnings growth potential of industrial landlords did not warrant the sector’s high valuations. However, the market did not share our concerns, and our underweight allocation and stock selection in the sector detracted from relative performance.

Escalating online sales and retail store closures pointed to continued challenges for retail landlords. Against this backdrop, regional malls were the only sector to experience a negative return in 2019. The Fund’s underweight allocation to regional malls contributed to relative performance, partially offset by stock selection in the sector. The Fund had a substantial underweight in the largest U.S. mall operator, which helped performance through most of the year, although its overweight in two other leading Class A mall companies detracted, as they experienced meaningful declines despite having what we believed were the capital and skills to renovate their properties to attract new tenants.

Residential housing continued to see favorable fundamentals due to a strong job market, a lack of new supply, worsening home affordability and positive demographic trends. Non-traditional segments manufactured homes and single family homes were among the best performers during the year. Our overweight allocations to the sectors (particularly investments centered in tech corridors of the West Coast) added to results. Returns for apartments were somewhat more modest, and our security selection in the sector—including an overweight position in UDR, which underperformed in part due to a subdued outlook from management—hindered relative performance.

Fundamentals for health care REITs generally improved during the year, particularly those with hospital and rehabilitation exposures. But despite a robust gain, health care REITs were relative laggards, impacted as interest rates moved higher in the fourth quarter. Our stock selection in the sector aided relative performance; one key contributor was a significant underweight in Ventas, which underperformed amid weak earnings (due mainly to pressure in its senior housing portfolio). An overweight position in Sabra Health Care REIT was also beneficial—the company has demonstrated improving fundamentals, and recent Medicare reimbursement trends for skilled nursing facilities have been favorable.

Self storage REITs faced challenging conditions, as increased supply prompted landlords to offer more aggressive discounts to attract new customers. Enhanced services from boutique self storage operators and new entries into the marketplace further strained profit margins. The timing of our allocations in the self storage sector was beneficial to the Fund’s performance.

Returns for office landlords were mixed, with companies in West Coast tech hubs benefiting from strong employment trends, while those centered on East Coast markets, particularly New York City, lagged amid tepid demand and rising supply. REITs have been adapting to the flexible office concept by adding co-working tenants or creating in-house flex-space brands. This generally requires higher capital outlays and results in increased density (fewer square feet per occupant), which was seen as a potential drag on office REIT profitability. The Fund’s stock selection in offices contributed to relative performance, as we favored West Coast property owners.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

Impact of Derivatives on Fund Performance

The Fund engaged in the buying and selling of single stock options with the intention of enhancing total returns and reducing overall volatility. These contracts did not have a material effect on the Fund’s total return for the 12-month period ended December 31, 2019.

Sincerely,

THOMAS N. BOHJALIAN	JON CHEIGH
Portfolio Manager	Portfolio Manager

            JASON A. YABLON

            Portfolio Manager

The views and opinions in the preceding commentary are subject to change without notice and are as of the date of the report. There is no guarantee that any market forecast set forth in the commentary will be realized. This material represents an assessment of the market environment at a specific point in time, should not be relied upon as investment advice and is not intended to predict or depict performance of any investment.

Visit Cohen & Steers online at cohenandsteers.com

For more information about the Cohen & Steers family of mutual funds, visit cohenandsteers.com. Here you will find fund net asset values, fund fact sheets and portfolio highlights, as well as educational resources and timely market updates.

Our website also provides comprehensive information about Cohen & Steers, including our most recent press releases, profiles of our senior investment professionals and their investment approach to each asset class. The Cohen & Steers family of mutual funds specializes in liquid real assets, including real estate securities, listed infrastructure and natural resource equities, as well as preferred securities and other income solutions.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

Performance Review (Unaudited)

Growth of a $1,000,000 Investment

Average Annual Total Returns—For Periods Ended December 31, 2019

	1 Year			5 Years			10 Years			Since Inceptionb
Cohen & Steers Institutional Realty Shares, Inc.		33.01	%		8.87	%		12.47	%		12.15	%

The performance data quoted represent past performance. Past performance is no guarantee of future results. The investment return and principal value of an investment will fluctuate and shares, if redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data quoted. Performance information current to the most recent month end can be obtained by visiting our website at cohenandsteers.com. Total return assumes the reinvestment of all dividends and distributions at NAV. The performance graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption of Fund shares. During the periods presented above, the investment manager waived fees and/or reimbursed expenses. Without this arrangement, performance would have been lower.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

Performance Review (Unaudited)—(Continued)

The annualized gross and net expense ratios, respectively, were 0.76% and 0.75% as disclosed in the May 1, 2019 prospectus. The investment manager has contractually agreed to waive its fee and/or reimburse expenses so that the Fund’s total annual operating expenses (excluding brokerage fees and commissions, taxes and, upon approval of the Fund’s Board of Directors, extraordinary expenses) never exceed 0.75% of the average daily net assets of the Fund. This commitment is currently expected to remain in place for the life of the Fund, can only be amended or terminated by agreement of the Fund’s Board of Directors and the investment manager and will terminate automatically in the event of termination of the investment management agreement between the Fund and the investment manager.

^a  The comparative indexes are not adjusted to reflect expenses or other fees that the U.S. Securities and Exchange Commission (SEC) requires to be reflected in the Fund’s performance. Index performance does not reflect the deduction of any fees, taxes or expenses. An investor cannot invest directly in an index. The Fund’s performance assumes the reinvestment of all dividends and distributions at NAV. For more information, including charges and expenses, please read the prospectus carefully before you invest.

^b  Inception date of February 14, 2000.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

Expense Example (Unaudited)

As a shareholder of the Fund, you incur two types of costs: (1) transaction costs and (2) ongoing costs including investment management fees and other Fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds.

The example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period July 1, 2019—December 31, 2019.

Actual Expenses

The first line of the following table provides information about actual account values and expenses. You may use the information in this line, together with the amount you invested, to estimate the expenses that you paid over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first line under the heading entitled “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

Hypothetical Example for Comparison Purposes

The second line of the following table provides information about hypothetical account values and hypothetical expenses based on the Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund’s actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing cost of investing in the Fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transaction costs. Therefore, the second line of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value July 1, 2019		Ending Account Value December 31, 2019		Expenses Paid During Perioda July 1, 2019— December 31, 2019
Actual (9.74% return)	$	1,000.00	$	1,097.40	$	3.96
Hypothetical (5% annual return before expenses)	$	1,000.00	$	1,021.42	$	3.82

^a  Expenses are equal to the Fund’s annualized net expense ratio of 0.75% multiplied by the average account value over the period, multiplied by 184/365 (to reflect the one-half year period).

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

December 31, 2019

Top Ten Holdings^a

(Unaudited)

Security	Value		% of Net Assets
American Tower Corp.	$	333,687,149		9.0
Equinix, Inc.		252,243,620		6.8
UDR, Inc.		197,835,444		5.3
Welltower, Inc.		189,612,082		5.1
Essex Property Trust, Inc.		157,866,657		4.3
SBA Communications Corp.		138,611,423		3.7
Prologis, Inc.		137,809,638		3.7
Public Storage		129,616,187		3.5
Duke Realty Corp.		127,659,239		3.4
Invitation Homes, Inc.		122,146,811		3.3

^a  Top ten holdings (excluding short-term investments) are determined on the basis of the value of individual securities held.

Sector Breakdown

(Based on Net Assets)

(Unaudited)

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

SCHEDULE OF INVESTMENTS

December 31, 2019

		Shares		Value
COMMON STOCK	98.8%
COMMUNICATIONS—TOWERS	14.9%
American Tower Corp.			1,451,950	$	333,687,149
Crown Castle International Corp.			573,256		81,488,340
SBA Communications Corp.			575,175		138,611,423
					553,786,912
CONSUMER, CYCLICAL—HOTELS, RESTAURANTS & LEISURE	0.5%
Boyd Gaming Corp.			635,851		19,037,379
REAL ESTATE	83.4%
DATA CENTERS	10.6%
CyrusOne, Inc.			854,379		55,902,018
Digital Realty Trust, Inc.			703,285		84,211,346
Equinix, Inc.			432,146		252,243,620
					392,356,984
DIVERSIFIED	1.9%
CBRE Group, Inc. Class Aa			811,856		49,758,654
Jones Lang LaSalle, Inc.			113,768		19,805,871
					69,564,525
HEALTH CARE	11.2%
Healthcare Trust of America, Inc., Class A			2,023,816		61,281,149
Healthpeak Properties, Inc.			1,114,302		38,409,990
Medical Properties Trust, Inc.			3,514,762		74,196,626
Sabra Health Care REIT, Inc.			2,482,995		52,987,113
Welltower, Inc.			2,318,563		189,612,082
					416,486,960
HOTEL	5.7%
Hilton Worldwide Holdings, Inc.			359,381		39,858,947
Host Hotels & Resorts, Inc.			2,989,540		55,455,967
Park Hotels & Resorts, Inc.			3,526,951		91,242,222
Red Rock Resorts, Inc. Class A			976,856		23,395,701
					209,952,837
INDUSTRIALS	7.2%
Duke Realty Corp.			3,682,124		127,659,239
Prologis, Inc.			1,545,991		137,809,638
					265,468,877

See accompanying notes to financial statements.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

SCHEDULE OF INVESTMENTS—(Continued)

December 31, 2019

		Shares		Value
NET LEASE	10.2%
Agree Realty Corp.			247,221	$	17,347,498
Realty Income Corp.			627,662		46,214,753
Spirit Realty Capital, Inc.			1,786,424		87,856,332
STORE Capital Corp.			915,199		34,082,011
VEREIT, Inc.			7,682,925		70,990,227
VICI Properties, Inc.			4,773,015		121,950,533
					378,441,354
OFFICE	5.7%
Boston Properties, Inc.			181,194		24,979,405
Empire State Realty Trust, Inc., Class A			1,904,143		26,581,836
Hudson Pacific Properties, Inc.			2,408,254		90,670,763
Kilroy Realty Corp.			815,714		68,438,405
					210,670,409
RESIDENTIAL	16.7%
APARTMENT	13.4%
Apartment Investment & Management Co., Class A			708,474		36,592,682
AvalonBay Communities, Inc.			504,411		105,774,987
Essex Property Trust, Inc.			524,718		157,866,657
UDR, Inc.			4,236,305		197,835,444
					498,069,770
SINGLE FAMILY	3.3%
Invitation Homes, Inc.			4,075,636		122,146,811
TOTAL RESIDENTIAL					620,216,581
SELF STORAGE	6.4%
Extra Space Storage, Inc.			1,035,093		109,326,523
Public Storage			608,641		129,616,187
					238,942,710
SHOPPING CENTERS	6.4%
COMMUNITY CENTER	3.2%
Regency Centers Corp.			567,509		35,804,143
SITE Centers Corp.			2,947,551		41,324,665
Urban Edge Properties			2,316,719		44,434,670
					121,563,478

See accompanying notes to financial statements.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

SCHEDULE OF INVESTMENTS—(Continued)

December 31, 2019

		Shares		Value
REGIONAL MALL	3.2%
Macerich Co. (The)			2,069,614	$	55,714,009
Simon Property Group, Inc.			294,543		43,875,125
Taubman Centers, Inc.			587,690		18,271,282
					117,860,416
TOTAL SHOPPING CENTERS					239,423,894
TIMBER	1.4%
Weyerhaeuser Co.			1,769,894		53,450,799
TOTAL REAL ESTATE					3,094,975,930
TOTAL COMMON STOCK (Identified cost—$3,043,746,501)					3,667,800,221
SHORT-TERM INVESTMENTS	0.7%
MONEY MARKET FUNDS
State Street Institutional Treasury Money Market Fund, Premier Class, 1.52%b			25,706,602		25,706,602
TOTAL SHORT-TERM INVESTMENTS (Identified cost—$25,706,602)					25,706,602
TOTAL INVESTMENTS IN SECURITIES (Identified cost—$3,069,453,103)	99.5%				3,693,506,823
OTHER ASSETS IN EXCESS OF LIABILITIES	0.5				18,587,620
NET ASSETS (Equivalent to $46.89 per share based on 79,173,528 shares of common stock outstanding)	100.0%			$	3,712,094,443

Glossary of Portfolio Abbreviations

REIT Real Estate Investment Trust

Note: Percentages indicated are based on the net assets of the Fund.

^a  Non-income producing security.

^b  Rate quoted represents the annualized seven-day yield.

See accompanying notes to financial statements.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

STATEMENT OF ASSETS AND LIABILITIES

December 31, 2019

ASSETS:
Investments in securities, at value (Identified cost—$3,069,453,103)	$	3,693,506,823
Receivable for:
Fund shares sold		17,425,521
Dividends		14,175,193
Investment securities sold		11,443,193
Other assets		26,008
Total Assets		3,736,576,738
LIABILITIES:
Payable for:
Investment securities purchased		19,592,388
Fund shares redeemed		2,577,023
Investment management fees		2,251,230
Directors’ fees		685
Other liabilities		60,969
Total Liabilities		24,482,295
NET ASSETS applicable to 79,173,528 shares of $0.001 par value of common stock outstanding	$	3,712,094,443
NET ASSET VALUE PER SHARE:
($3,712,094,443 ÷ 79,173,528 shares outstanding)	$	46.89
NET ASSETS consist of:
Paid-in capital	$	2,976,756,236
Total distributable earnings/(accumulated loss)		735,338,207
	$	3,712,094,443

See accompanying notes to financial statements.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

STATEMENT OF OPERATIONS

For the Year Ended December 31, 2019

Investment Income:
Dividend income	$	86,487,896
Expenses:
Investment management fees		25,241,568
Registration and filing fees		154,761
Directors’ fees and expenses		150,182
Miscellaneous		24,075
Total Expenses		25,570,586
Reduction of Expenses (See Note 2)		(329,199	)
Net Expenses		25,241,387
Net Investment Income (Loss)		61,246,509
Net Realized and Unrealized Gain (Loss):
Net realized gain (loss) on:
Investments in securities		386,588,541
Written option contracts		313,372
Net realized gain (loss)		386,901,913
Net change in unrealized appreciation (depreciation) on investments in securities		452,462,328
Net Realized and Unrealized Gain (Loss)		839,364,241
Net Increase (Decrease) in Net Assets Resulting from Operations	$	900,610,750

See accompanying notes to financial statements.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

STATEMENT OF CHANGES IN NET ASSETS

	For the Year Ended December 31, 2019			For the Year Ended December 31, 2018
Change in Net Assets:
From Operations:
Net investment income (loss)	$	61,246,509		$	61,819,561
Net realized gain (loss)		386,901,913			138,104,769
Net change in unrealized appreciation (depreciation)		452,462,328			(312,240,365	)
Net increase (decrease) in net assets resulting from operations		900,610,750			(112,316,035	)
Distributions to Shareholders		(364,985,667	)		(166,537,254	)
Capital Stock Transactions:
Increase (decrease) in net assets from Fund share transactions		516,871,165			150,538,693
Total increase (decrease) in net assets		1,052,496,248			(128,314,596	)
Net Assets:
Beginning of year		2,659,598,195			2,787,912,791
End of year	$	3,712,094,443		$	2,659,598,195

See accompanying notes to financial statements.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

FINANCIAL HIGHLIGHTS

The following table includes selected data for a share outstanding throughout each year and other

performance information derived from the financial statements. It should be read in conjunction with the financial statements and notes thereto.

	For the Year Ended December 31,
Per Share Operating Data:	2019			2018			2017			2016			2015
Net asset value, beginning of year		$39.25			$43.32			$43.18			$45.93			$50.06
Income (loss) from investment operations:
Net investment income (loss)a		0.84			0.93			0.79			0.83			0.72	b
Net realized and unrealized gain (loss)		11.80			(2.51	)c		2.37			1.87			1.41
Total from investment operations		12.64			(1.58	)		3.16			2.70			2.13
Less dividends and distributions to shareholders from:
Net investment income		(0.63	)		(0.75	)		(0.86	)		(0.82	)		(0.68	)
Net realized gain		(4.37	)		(1.74	)		(2.16	)		(4.63	)		(5.58	)
Total dividends and distributions to shareholders		(5.00	)		(2.49	)		(3.02	)		(5.45	)		(6.26	)
Net increase (decrease) in net asset value		7.64			(4.07	)		0.14			(2.75	)		(4.13	)
Net asset value, end of year		$46.89			$39.25			$43.32			$43.18			$45.93
Total returnd		33.01	%		–4.01	%c		7.47	%		5.91	%		5.23	%
Ratios/Supplemental Data:
Net assets, end of year (in millions)		$3,712.1			$2,659.6			$2,787.9			$2,740.8			$2,931.5
Ratios to average daily net assets:
Expenses (before expense reduction)		0.76	%		0.78	%c		0.77	%		0.76	%		0.76	%
Expenses (net of expense reduction)		0.75	%		0.77	%c		0.75	%		0.75	%		0.75	%
Net investment income (loss) (before expense reduction)		1.81	%		2.22	%		1.77	%		1.77	%		1.46	%
Net investment income (loss) (net of expense reduction)		1.82	%		2.23	%		1.79	%		1.78	%		1.47	%
Portfolio turnover rate		82	%		68	%		76	%		79	%		60	%

^a  Calculation based on average shares outstanding.

^b  13.2% of gross income was attributable to dividends paid by Simon Property Group for the year ended December 31, 2015.

^c  During the reporting period the Fund settled legal claims against two issuers of securities previously held by the Fund. As a result, the net realized and unrealized gain (loss) on investments per share includes proceeds received from the settlements. Without these proceeds the net realized and unrealized gain (loss) on investments per share would have been $(2.56). Additionally, the expense ratio includes extraordinary expenses related to the direct action. Without these expenses, the ratio of expenses to average daily net assets (before expense reduction and net of expense reduction) would have been 0.76% and 0.75%, respectively. Excluding the proceeds from and expenses relating to the settlements, the total return would have been -4.12%.

^d  Return assumes the reinvestment of all dividends and distributions at net asset value.

See accompanying notes to financial statements.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

NOTES TO FINANCIAL STATEMENTS

Note 1. Organization and Significant Accounting Policies

Cohen & Steers Institutional Realty Shares, Inc. (the Fund) was incorporated under the laws of the State of Maryland on October 13, 1999 and is registered under the Investment Company Act of 1940 (the 1940 Act) as a non-diversified, open-end management investment company. The Fund’s investment objective is total return.

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. The Fund is an investment company and, accordingly, follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board Accounting Standards Codification (ASC) Topic 946—Investment Companies. The accounting policies of the Fund are in conformity with accounting principles generally accepted in the United States of America (GAAP). The preparation of the financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of income and expenses during the reporting period. Actual results could differ from those estimates.

Portfolio Valuation: Investments in securities that are listed on the New York Stock Exchange (NYSE) are valued, except as indicated below, at the last sale price reflected at the close of the NYSE on the business day as of which such value is being determined. If there has been no sale on such day, the securities are valued at the mean of the closing bid and ask prices on such day or, if no ask price is available, at the bid price. Exchange-traded options are valued at their last sale price as of the close of options trading on applicable exchanges on the valuation date. In the absence of a last sale price on such day, options are valued at the average of the quoted bid and ask prices as of the close of business. Over-the-counter (OTC) options are valued based upon prices provided by a third-party pricing service or counterparty.

Securities not listed on the NYSE but listed on other domestic or foreign securities exchanges (including NASDAQ) are valued in a similar manner. Securities traded on more than one securities exchange are valued at the last sale price reflected at the close of the exchange representing the principal market for such securities on the business day as of which such value is being determined.

Readily marketable securities traded in the OTC market, including listed securities whose primary market is believed by Cohen & Steers Capital Management, Inc. (the investment manager) to be OTC, are valued on the basis of prices provided by a third-party pricing service or third-party broker-dealers when such prices are believed by the investment manager, pursuant to delegation by the Board of Directors, to reflect the fair value of such securities.

Short-term debt securities with a maturity date of 60 days or less are valued at amortized cost, which approximates fair value. Investments in open-end mutual funds are valued at net asset value (NAV).

The policies and procedures approved by the Fund’s Board of Directors delegate authority to make fair value determinations to the investment manager, subject to the oversight of the Board of Directors. The investment manager has established a valuation committee (Valuation Committee) to administer, implement and oversee the fair valuation process according to the policies and procedures

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

NOTES TO FINANCIAL STATEMENTS—(Continued)

approved annually by the Board of Directors. Among other things, these procedures allow the Fund to utilize independent pricing services, quotations from securities and financial instrument dealers and other market sources to determine fair value.

Securities for which market prices are unavailable, or securities for which the investment manager determines that the bid and/or ask price or a counterparty valuation does not reflect market value, will be valued at fair value, as determined in good faith by the Valuation Committee, pursuant to procedures approved by the Fund’s Board of Directors. Circumstances in which market prices may be unavailable include, but are not limited to, when trading in a security is suspended, the exchange on which the security is traded is subject to an unscheduled close or disruption or material events occur after the close of the exchange on which the security is principally traded. In these circumstances, the Fund determines fair value in a manner that fairly reflects the market value of the security on the valuation date based on consideration of any information or factors it deems appropriate. These may include, but are not limited to, recent transactions in comparable securities, information relating to the specific security and developments in the markets.

The Fund’s use of fair value pricing may cause the NAV of Fund shares to differ from the NAV that would be calculated using market quotations. Fair value pricing involves subjective judgments and it is possible that the fair value determined for a security may be materially different than the value that could be realized upon the sale of that security.

Fair value is defined as the price that the Fund would expect to receive upon the sale of an investment or expect to pay to transfer a liability in an orderly transaction with an independent buyer in the principal market or, in the absence of a principal market, the most advantageous market for the investment or liability. The hierarchy of inputs that are used in determining the fair value of the Fund’s investments is summarized below.

• Level 1—quoted prices in active markets for identical investments

• Level 2—other significant observable inputs (including quoted prices for similar investments, interest rates, credit risk, etc.)

• Level 3—significant unobservable inputs (including the Fund’s own assumptions in determining the fair value of investments)

The inputs or methodology used for valuing investments may or may not be an indication of the risk associated with those investments. Changes in valuation techniques may result in transfers into or out of an assigned level within the disclosure hierarchy.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

NOTES TO FINANCIAL STATEMENTS—(Continued)

The following is a summary of the inputs used as of December 31, 2019 in valuing the Fund’s investments carried at value:

	Total		Quoted Prices in Active Markets for Identical Investments (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Common Stock	$	3,667,800,221	$	3,667,800,221	$	—	$	—
Short-Term Investments		25,706,602		—		25,706,602		—
Total Investments in Securitiesa	$	3,693,506,823	$	3,667,800,221	$	25,706,602	$	—

^a  Portfolio holdings are disclosed individually on the Schedule of Investments.

Security Transactions and Investment Income: Security transactions are recorded on trade date. Realized gains and losses on investments sold are recorded on the basis of identified cost. Interest income, which includes the amortization of premiums and accretion of discounts, is recorded on the accrual basis. Dividend income is recorded on the ex-dividend date. Distributions from REITs are recorded as ordinary income, net realized capital gain or return of capital based on information reported by the REITs and management’s estimates of such amounts based on historical information. These estimates are adjusted when the actual source of distributions is disclosed by the REITs and actual amounts may differ from the estimated amounts.

Options: The Fund may purchase and write exchange-listed and OTC put or call options on securities, stock indices and other financial instruments for hedging purposes, to enhance portfolio returns and/or reduce overall volatility.

When the Fund writes (sells) an option, an amount equal to the premium received by the Fund is recorded on the Statement of Assets and Liabilities as a liability. The amount of the liability is subsequently marked-to-market to reflect the current market value of the option written. When an option expires, the Fund realizes a gain on the option to the extent of the premium received. Premiums received from writing options which are exercised or closed are added to or offset against the proceeds or amount paid on the transaction to determine the realized gain or loss. If a put option on a security is exercised, the premium reduces the cost basis of the security purchased by the Fund. If a call option is exercised, the premium is added to the proceeds of the security sold to determine the realized gain or loss. The Fund, as writer of an option, bears the market risk of an unfavorable change in the price of the underlying investment. Other risks include the possibility of an illiquid options market or the inability of the counterparties to fulfill their obligations under the contracts.

Put and call options purchased are accounted for in the same manner as portfolio securities. Premiums paid for purchasing options which expire are treated as realized losses. Premiums paid for purchasing options which are exercised or closed are added to the amounts paid or offset against the proceeds on the underlying investment transaction to determine the realized gain or loss when the

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

NOTES TO FINANCIAL STATEMENTS—(Continued)

underlying transaction is executed. The risk associated with purchasing an option is that the Fund pays a premium whether or not the option is exercised. Additionally, the Fund bears the risk of loss of the premium and change in market value should the counterparty not perform under the contract.

At December 31, 2019, the fund did not have any options contracts outstanding.

Dividends and Distributions to Shareholders: Dividends from net investment income and capital gain distributions are determined in accordance with U.S. federal income tax regulations, which may differ from GAAP. Dividends from net investment income, if any, are declared and paid quarterly. Net realized capital gains, unless offset by any available capital loss carryforward, are typically distributed to shareholders at least annually. Dividends and distributions to shareholders are recorded on the ex-dividend date and are automatically reinvested in full and fractional shares of the Fund based on the NAV per share at the close of business on the payable date, unless the shareholder has elected to have them paid in cash.

Dividends from net investment income are subject to recharacterization for tax purposes. Based upon the results of operations for the year ended December 31, 2019, a portion of the dividends have been reclassified to distributions from net realized gain.

Income Taxes: It is the policy of the Fund to continue to qualify as a regulated investment company (RIC), if such qualification is in the best interest of the shareholders, by complying with the requirements of Subchapter M of the Internal Revenue Code applicable to RICs, and by distributing substantially all of its taxable earnings to its shareholders. Also, in order to avoid the payment of any federal excise taxes, the Fund will distribute substantially all of its net investment income and net realized gains on a calendar year basis. Accordingly, no provision for federal income or excise tax is necessary. Management has analyzed the Fund’s tax positions taken on federal and applicable state income tax returns as well as its tax positions in non-U.S. jurisdictions in which it trades for all open tax years and has concluded that as of December 31, 2019, no additional provisions for income tax are required in the Fund’s financial statements. The Fund’s tax positions for the tax years for which the applicable statutes of limitations have not expired are subject to examination by the Internal Revenue Service, state departments of revenue and by foreign tax authorities.

Note 2. Investment Management Fees and Other Transactions with Affiliates

Investment Management Fees: Cohen & Steers Capital Management, Inc. serves as the Fund’s investment manager pursuant to an investment management agreement (the investment management agreement). Under the terms of the investment management agreement, the investment manager provides the Fund with day-to-day investment decisions and generally manages the Fund’s investments in accordance with the stated policies of the Fund, subject to the supervision of the Board of Directors.

For the services provided to the Fund, the investment manager receives a fee, accrued daily and paid monthly, at the annual rate of 0.75% of the average daily net assets of the Fund.

The investment manager is also responsible, under the investment management agreement, for the performance of certain administrative functions for the Fund. Additionally, the investment manager pays certain expenses of the Fund, including, but not limited to, administrative and custody fees, transfer agent fees, professional fees, and reports to shareholders.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

NOTES TO FINANCIAL STATEMENTS—(Continued)

The investment manager has contractually agreed to waive its fee and/or reimburse the Fund so that the Fund’s total annual operating expenses (excluding brokerage fees and commissions, taxes, and, upon approval of the Board of Directors, extraordinary expenses) never exceed 0.75% of the average daily net assets of the Fund. This commitment is currently expected to remain in place for the life of the Fund, can only be amended or terminated by agreement of the Fund’s Board of Directors and the investment manager and will terminate automatically in the event of termination of the investment management agreement between the investment manager and the Fund. For the year ended December 31, 2019, fees waived and/or expenses reimbursed totaled $329,199.

Directors’ and Officers’ Fees: Certain directors and officers of the Fund are also directors, officers, and/or employees of the investment manager. The Fund does not pay compensation to directors and officers affiliated with the investment manager.

Other: As of December 31, 2019, approximately 17% of the Fund’s outstanding shares were owned by shareholders investing either directly or indirectly through an account, platform or program sponsored by one financial institution. Investment and asset allocation decisions by either a direct shareholder or financial institution regarding the account, platform or program through which multiple shareholders invest may result in subscription and redemption decisions that have a significant impact on the assets, expenses and trading activities of the Fund. Such a decision may cause the Fund to sell assets at disadvantageous times or prices, and may negatively affect the Fund’s NAV and performance.

Note 3. Purchases and Sales of Securities

Purchases and sales of securities, excluding short-term investments, for the year ended December 31, 2019, totaled $2,927,342,226 and $2,719,097,558, respectively.

Note 4. Derivative Investments

The following table presents the effect of derivatives held during the year ended December 31, 2019, along with the respective location in the financial statements.

Statement of Operations

Derivatives	Location	Realized Gain (Loss)			Change in Unrealized Appreciation (Depreciation)
Equity Risk:
Purchased Option Contractsa	Net Realized and Unrealized Gain (Loss)	$	(438,977	)	$	—
Written Option Contracts	Net Realized and Unrealized Gain (Loss)		313,372			—

^a  Purchased options are included in net realized gain (loss) and change in unrealized appreciation (depreciation) on investments in securities.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

NOTES TO FINANCIAL STATEMENTS—(Continued)

The following summarizes the volume of the Fund’s option contracts activity for the year ended December 31, 2019:

	Purchased Option Contracts		Written Option Contracts
Average Notional Amounta,b	$	41,106,716	$	44,361,703

^a  Average notional amounts represent the average for all months in which the Fund had option contracts outstanding at month end. For the period, this represents one month for purchased option contracts and four months for written option contracts.

^b  Notional amount is calculated using the number of contracts multiplied by notional contract size multiplied by the underlying price.

Note 5. Income Tax Information

The tax character of dividends and distributions paid was as follows:

	For the Year Ended December 31,
	2019		2018
Ordinary income	$	183,752,797	$	53,145,417
Long-term capital gain		181,232,870		113,391,837
Total dividends and distributions	$	364,985,667	$	166,537,254

As of December 31, 2019, the tax-basis components of accumulated earnings, the federal tax cost and net unrealized appreciation (depreciation) in value of investments held were as follows:

Cost of investments in securities for federal income tax purposes	$	3,077,995,271
Gross unrealized appreciation on investments	$	675,668,260
Gross unrealized depreciation on investments		(60,156,708	)
Net unrealized appreciation (depreciation) on investments	$	615,511,552
Undistributed ordinary income	$	25,000,990
Undistributed long-term capital gains	$	87,412,111

As of December 31, 2019, the Fund had temporary book/tax differences primarily attributable to wash sales on portfolio securities and certain REIT dividends, and permanent book/tax differences primarily attributable to Fund redemptions used as distributions and prior year REIT distribution adjustments. To reflect reclassifications arising from the permanent differences, paid-in capital was credited $11,203,088 and total distributable earnings/(accumulated loss) was charged $11,203,088. Net assets were not affected by this reclassification.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

NOTES TO FINANCIAL STATEMENTS—(Continued)

Note 6. Capital Stock

The Fund is authorized to issue 100 million shares of capital stock, at a par value of $0.001 per share. The Fund’s Board of Directors may increase or decrease the aggregate number of shares of common stock that the Fund has authority to issue. Transactions in Fund shares were as follows:

	For the Year Ended December 31, 2019						For the Year Ended December 31, 2018
	Shares			Amount			Shares			Amount
Sold		19,413,828		$	892,893,894			19,074,565		$	797,341,690
Issued as reinvestment of dividends and distributions		7,032,773			321,654,362			3,354,846			143,310,382
Redeemed		(15,037,285	)		(697,677,091	)		(19,028,484	)		(790,113,379	)
Net increase (decrease)		11,409,316		$	516,871,165			3,400,927		$	150,538,693

Note 7. Other Risks

Common Stock Risk: While common stocks have historically generated higher average returns than fixed-income securities over the long-term, common stocks have also experienced significantly more volatility in those returns, although under certain market conditions, fixed-income investments may have comparable or greater price volatility. The value of common stocks and other equity securities will fluctuate in response to developments concerning the company, political and regulatory circumstances, the stock market, and the economy. In the short term, stock prices can fluctuate dramatically in response to these developments. Different parts of the market and different types of equity securities can react differently to these developments. For example, stocks of large companies can react differently than stocks of smaller companies, and value stocks (stocks of companies that are undervalued by various measures and have potential for long-term capital appreciation), can react differently from growth stocks (stocks of companies with attractive cash flow returns on invested capital and earnings that are expected to grow). These developments can affect a single company, all companies within the same industry, economic sector or geographic region, or the stock market as a whole.

Real Estate Market Risk: Since the Fund concentrates its assets in companies engaged in the real estate industry, an investment in the Fund will be closely linked to the performance of the real estate markets. Risks of investing in real estate securities include falling property values due to increasing vacancies, declining rents resulting from economic, legal, tax, political or technological developments, lack of liquidity, limited diversification, and sensitivity to certain economic factors such as interest-rate changes and market recessions. Real estate company prices also may drop because of the failure of borrowers to pay their loans and poor management, and residential developers, in particular, could be negatively impacted by falling home prices, slower mortgage origination and rising construction costs. The risks of investing in REITs are similar to those associated with direct investments in real estate securities.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

NOTES TO FINANCIAL STATEMENTS—(Continued)

REIT Risk: In addition to the risks of securities linked to the real estate industry, REITs are subject to certain other risks related to their structure and focus. REITs are dependent upon management skills and generally may not be diversified. REITs are also subject to heavy cash flow dependency, defaults by borrowers and self-liquidation. In addition, REITs could possibly fail to (i) qualify for pass-through of income under applicable tax law, or (ii) maintain their exemptions from registration under the 1940 Act. The above factors may also adversely affect a borrower’s or a lessee’s ability to meet its obligations to the REIT. In the event of a default by a borrower or lessee, the REIT may experience delays in enforcing its rights as a mortgagee or lessor and may incur substantial costs associated with protecting its investments.

Small- and Medium-Sized Companies Risk: Real estate companies in the industry tend to be small- to medium-sized companies in relation to the equity markets as a whole. There may be less trading in a smaller company’s stock, which means that buy and sell transactions in that stock could have a larger impact on the stock’s price than is the case with larger company stocks. Smaller companies also may have fewer lines of business so that changes in any one line of business may have a greater impact on a smaller company’s stock price than is the case for a larger company. Further, smaller company stocks may perform differently in different cycles than larger company stocks. Accordingly, real estate company shares can, and at times will, perform differently than large company stocks.

Non-Diversification Risk: As a “non-diversified” investment company, the Fund can invest in fewer individual companies than a diversified investment company. As a result, the Fund is more susceptible to any single political, regulatory or economic occurrence and to the financial condition of individual issuers in which it invests. The Fund’s relative lack of diversity may subject investors to greater risk of loss than a fund that has a diversified portfolio.

Regulatory Risk: The U.S. government has proposed and adopted multiple regulations that could have a long-lasting impact on the Fund and on the mutual fund industry in general. The SEC’s final rules and amendments that modernize reporting and disclosure and require the implementation of a Liquidity Risk Management Program, along with other potential upcoming regulations, could, among other things, restrict the Fund’s ability to engage in transactions, impact flows into the Fund and/or increase overall expenses of the Fund. In addition, the SEC, Congress, various exchanges and regulatory and self-regulatory authorities, both domestic and foreign, have undertaken reviews of the use of derivatives by registered investment companies, which could affect the nature and extent of instruments used by the Fund. While the full extent of all of these regulations is still unclear, these regulations and actions may adversely affect both the Fund and the instruments in which the Fund invests and its ability to execute its investment strategy. Similarly, regulatory developments in other countries may have an unpredictable and adverse impact on the Fund.

Large Shareholder Risk: The Fund may have one or more large shareholders or a group of shareholders investing in Fund shares indirectly through an account, platform or program sponsored by a financial institution. Investment and asset allocation decisions by such financial institutions regarding the account, platform or program through which multiple shareholders invest may result in subscription and redemption decisions that have a significant impact on the assets, expenses and trading activities

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

NOTES TO FINANCIAL STATEMENTS—(Continued)

of the Fund. Such a decision may cause the Fund to sell assets (or invest cash) at disadvantageous times or prices, increase or accelerate taxable gains or transaction costs and may negatively affect the Fund’s NAV, performance, or ability to satisfy redemptions in a timely manner.

This is not a complete list of the risks of investing in the Fund. For additional information concerning the risks of investing in the Fund, please consult the Fund’s prospectus.

Note 8. Other

In the normal course of business, the Fund enters into contracts that provide general indemnifications. The Fund’s maximum exposure under these arrangements is dependent on claims that may be made against the Fund in the future and, therefore, cannot be estimated; however, based on experience, the risk of material loss from such claims is considered remote.

Note 9. Subsequent Events

Management has evaluated events and transactions occurring after December 31, 2019 through the date that the financial statements were issued, and has determined that no additional disclosure in the financial statements is required.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Directors and Shareholders of

Cohen & Steers Institutional Realty Shares, Inc.

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Cohen & Steers Institutional Realty Shares, Inc. (the “Fund”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statement of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2019 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the five years in the period ended December 31, 2019 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Fund’s management. Our responsibility is to express an opinion on the Fund’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the custodian, transfer agent and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

/s/ PricewaterhouseCoopers LLP

New York, New York

February 21, 2020

We have served as the auditor of one or more investment companies in the Cohen & Steers family of mutual funds since 1991.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

TAX INFORMATION—2019 (Unaudited)

For the calendar year ended December 31, 2019, for individual taxpayers, the Fund designates $2,378,790 as qualified dividend income eligible for reduced tax rates, long-term capital gain distributions of $191,811,046 taxable at the maximum 20% rate, long-term capital gain distributions of $630,863 taxable at 25% maximum rate, short-term capital gain distributions of $137,414,526 and $59,904,583 as qualified business income eligible for the 20% deduction. In addition, for corporate taxpayers, 0.28% of the ordinary dividends paid qualified for the dividends received deduction (DRD).

OTHER INFORMATION

A description of the policies and procedures that the Fund uses to determine how to vote proxies relating to portfolio securities is available (i) without charge, upon request, by calling 800-330-7348, (ii) on our website at cohenandsteers.com or (iii) on the SEC’s website at http://www.sec.gov. In addition, the Fund’s proxy voting record for the most recent 12-month period ended June 30 is available by August 31 of each year (i) without charge, upon request, by calling 800-330-7348 or (ii) on the SEC’s website at http://www.sec.gov.

Disclosures of the Fund’s complete holdings are required to be made monthly on Form N-PORT, with every third month made available to the public by the SEC 60 days after the end of the Fund’s fiscal quarter. Previously, the Fund filed its complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year on Form N-Q, which has now been rescinded. Both the Fund’s Form N-Q and Form N-PORT are available (i) without charge, upon request, by calling 800-330-7348 or (ii) on the SEC’s website at http://www.sec.gov.

Please note that distributions paid by the Fund to shareholders are subject to recharacterization for tax purposes and are taxable up to the amount of the Fund’s investment company taxable income and net realized gains. Distributions in excess of the Fund’s net investment company taxable income and realized gains are a return of capital distributed from the Fund’s assets. The final tax treatment of all distributions is reported to shareholders on their 1099-DIV forms, which are mailed after the close of each calendar year.

Benchmark Change

On December 4, 2018, the Fund’s Board of Directors approved a change to the Fund’s benchmark from the FTSE Nareit Equity REITs Index to the FTSE Nareit All Equity REITs Index, effective after the close of business on March 31, 2019.

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

MANAGEMENT OF THE FUND

The business and affairs of the Fund are managed under the direction of the Board of Directors. The Board of Directors approves all significant agreements between the Fund and persons or companies furnishing services to it, including the Fund’s agreements with its investment manager, administrator, co-administrator, custodian and transfer agent. The management of the Fund’s day-to-day operations is delegated to its officers, the investment manager, administrator and co-administrator, subject always to the investment objective and policies of the Fund and to the general supervision of the Board of Directors.

The Board of Directors and officers of the Fund and their principal occupations during at least the past five years are set forth below. The statement of additional information (SAI) includes additional information about fund directors and is available, without charge, upon request by calling 800-330-7348.

Name, Address and Year of Birth1	Position(s) Held With Fund	Term of Office2	Principal Occupation During At Least The Past 5 Years (Including Other Directorships Held)	Number of Funds Within Fund Complex Overseen by Director (Including the Fund)		Length of Time Served3
Interested Directors4
Robert H. Steers 1953	Director, Chairman	Until Next Election of Directors	Chief Executive Officer of Cohen & Steers Capital Management, Inc. (CSCM or the Advisor) and its parent, Cohen & Steers, Inc. (CNS) since 2014. Prior to that, Co-Chairman and Co-Chief Executive Officer of the Advisor since 2003 and CNS since 2004. Prior to that, Chairman of the Advisor; Vice President of Cohen & Steers Securities, LLC.		20	Since 1991
Joseph M. Harvey 1963	Director	Until Next Election of Directors	President of the Advisor (since 2003) and President of CNS (since 2004). Chief Investment Officer of CSCM from 2003 to 2019. Prior to that, Senior Vice President and Director of Investment Research of CSCM.		20	Since 2014

(table continued on next page)

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

(table continued from previous page)

Name, Address and Year of Birth1	Position(s) Held With Fund	Term of Office2	Principal Occupation During At Least The Past 5 Years (Including Other Directorships Held)	Number of Funds Within Fund Complex Overseen by Director (Including the Fund)		Length of Time Served3
Disinterested Directors
Michael G. Clark 1965	Director	Until Next Election of Directors	CPA and CFA; from 2006 to 2011, President and Chief Executive Officer of DWS Funds and Managing Director of Deutsche Asset Management.		20	Since 2011
George Grossman 1953	Director	Until Next Election of Directors	Attorney-at-law.		20	Since 1993
Dean A. Junkans 1959	Director	Until Next Election of Directors	CFA; Advisor to SigFig (a registered investment advisor) since July, 2018; Adjunct Professor and Executive–In–Residence, Bethel University Since 2015; Chief Investment Officer at Wells Fargo Private Bank from 2004 to 2014 and Chief Investment Officer of the Wealth, Brokerage and Retirement group at Wells Fargo & Company from 2011 to 2014; former Member and Chair, Claritas Advisory Committee at the CFA Institute from 2013 to 2015; Board Member and Investment Committee member, Bethel University Foundation since 2010; formerly Corporate Executive Board Member of the National Chief Investment Officers Circle, 2010 to 2015; formerly, Member of the Board of Governors of the University of Wisconsin Foundation, River Falls, 1996 to 2004; U.S. Army Veteran, Gulf War.		20	Since 2015

(table continued on next page)

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COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

(table continued from previous page)

Name, Address and Year of Birth1	Position(s) Held With Fund	Term of Office2	Principal Occupation During At Least The Past 5 Years (Including Other Directorships Held)	Number of Funds Within Fund Complex Overseen by Director (Including the Fund)	Length of Time Served3
Gerald J. Maginnis 1955	Director	Until Next Election of Directors	Philadelphia Office Managing Partner, KPMG LLP from 2006 to 2015; Partner in Charge, KPMG Pennsylvania Audit Practice from 2002 to 2008; President, Pennsylvania Institute of Certified Public Accountants (PICPA) from 2014 to 2015; Member, PICPA Board of Directors from 2012 to 2016; Member, Council of the American Institute of Certified Public Accountants (AICPA) from 2013 to 2017; Member, Board of Trustees of AICPA Foundation since 2015.	20	Since 2015
Jane F. Magpiong 1960	Director	Until Next Election of Directors	President, Untap Potential since 2013; Senior Managing Director, TIAA-CREF, from 2011 to 2013; National Head of Wealth Management, TIAA-CREF, from 2008 to 2011; and prior to that, President, Bank of America Private Bank from 2005 to 2008.	20	Since 2015

(table continued on next page)

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(table continued from previous page)

Name, Address and Year of Birth1	Position(s) Held With Fund	Term of Office2	Principal Occupation During At Least The Past 5 Years (Including Other Directorships Held)	Number of Funds Within Fund Complex Overseen by Director (Including the Fund)	Length of Time Served3
Daphne L. Richards 1966	Director	Until Next Election of Directors	Independent Director of Cartica Management, LLC since 2015; Investment Committee Member of the Berkshire Taconic Community Foundation since 2015 and Member of the Advisory Board of Northeast Dutchess Fund Since 2016; President and CIO of Ledge Harbor Management since 2016; formerly at Bessemer Trust Company from 1999 to 2014 ; prior thereto, held investment positions at Frank Russell Company from 1996 to 1999, Union Bank of Switzerland from 1993 to 1996; Credit Suisse from 1990 to 1993 ; and Hambros International Venture Capital Fund from 1988 to 1989.	20	Since 2017

(table continued on next page)

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(table continued from previous page)

Name, Address and Year of Birth1	Position(s) Held With Fund	Term of Office2	Principal Occupation During At Least The Past 5 Years (Including Other Directorships Held)	Number of Funds Within Fund Complex Overseen by Director (Including the Fund)	Length of Time Served3
C. Edward Ward, Jr. 1946	Director	Until Next Election of Directors	Member of The Board of Trustees of Manhattan College, Riverdale,New York from 2004 to 2014; formerly, Director of closed-end fund management for the NYSE where he worked from 1979 to 2004.	20	Since 2004

¹  The address for each director is 280 Park Avenue, New York, NY 10017.

²  On March 12, 2008, the Board of Directors adopted a mandatory retirement policy stating a Director must retire from the Board on December 31st of the year in which he or she turns 75 years of age.

³  The length of time served represents the year in which the Director was first elected or appointed to any fund in the Cohen & Steers fund complex.

⁴  “Interested person” as defined in the 1940 Act, of the Fund because of affiliation with CSCM (Interested Directors).

30

COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

The officers of the Fund (other than Messrs. Steers and Harvey, whose biographies are provided above), their address, their year of birth and their principal occupations for at least the past five years are set forth below.

Name, Address and year of Birth1	Position(s) Held With Fund	Principal Occupation During At least the Past 5 Years	Length of Time Served2
Adam M. Derechin 1964	President and Chief Executive Officer	Chief Operating Officer of CSCM since 2003 and CNS since 2004.	Since 2005
James Giallanza 1966	Chief Financial Officer	Executive Vice President of CSCM since 2014. Prior to that, Senior Vice President of CSCM since 2006.	Since 2006
Lisa D. Phelan 1968	Chief Compliance Officer	Executive Vice President of CSCM since 2015. Prior to that, Senior Vice President of CSCM since 2008. Chief Compliance Officer of CSCM, the Cohen & Steers funds, Cohen & Steers Asia Limited and CSSL since 2007, 2006, 2005 and 2004, respectively.	Since 2006
Dana A. DeVivo 1981	Secretary and Chief Legal Officer	Senior Vice President of CSCM since 2019. Prior to that, Vice President of CSCM since 2013.	Since 2015
Albert Laskaj 1977	Treasurer	Senior Vice President of CSCM since 2019. Prior to that, Vice President of CSCM since 2015. Prior to that, Director of Legg Mason & Co. since 2013.	Since 2015
Stephen Murphy 1966	Vice President	Senior Vice President of CSCM since 2019. Prior to that, Managing Director at Mirae Asset Securities (USA) Inc. since 2017. Prior to that, Vice President and Chief Compliance Officer of Weiss Multi-Strategy Advisers LLC since 2011.	Since 2019
Thomas N. Bohjalian 1965	Vice President	Executive Vice President of CSCM since 2012. Prior to that, Senior Vice President of CSCM since 2006.	Since 2006
Jon Cheigh 1972	Vice President	Chief Investment Officer of CSCM since 2019. Prior to that, Executive Vice President of CSCM since 2012. Prior to that, Senior Vice President of CSCM since 2007.	Since 2007
Jason A. Yablon 1979	Vice President	Senior Vice President of CSCM since 2014. Prior to that, Vice President of CSCM since 2008.	Since 2012

¹  The address of each officer is 280 Park Avenue, New York, NY 10017.

²  Officers serve one-year terms. The length of time served represents the year in which the officer was first elected as an officer of any fund in the Cohen & Steers fund complex. All of the officers listed above are officers of one or more of the other funds in the complex.

31

COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

Cohen & Steers Privacy Policy

Facts	What Does Cohen & Steers Do With Your Personal Information?
Why?	Financial companies choose how they share your personal information. Federal law gives consumers the right to limit some but not all sharing. Federal law also requires us to tell you how we collect, share, and protect your personal information. Please read this notice carefully to understand what we do.
What?	The types of personal information we collect and share depend on the product or service you have with us. This information can include: • Social Security number and account balances • Transaction history and account transactions • Purchase history and wire transfer instructions
How?	All financial companies need to share customers’ personal information to run their everyday business. In the section below, we list the reasons financial companies can share their customers’ personal information; the reasons Cohen & Steers chooses to share; and whether you can limit this sharing.

Reasons we can share your personal information	Does Cohen & Steers share?	Can you limit this sharing?
For our everyday business purposes— such as to process your transactions, maintain your account(s), respond to court orders and legal investigations, or reports to credit bureaus	Yes	No
For our marketing purposes— to offer our products and services to you	Yes	No
For joint marketing with other financial companies—	No	We don’t share
For our affiliates’ everyday business purposes— information about your transactions and experiences	No	We don’t share
For our affiliates’ everyday business purposes— information about your creditworthiness	No	We don’t share
For our affiliates to market to you—	No	We don’t share
For non-affiliates to market to you—	No	We don’t share
Questions?    Call 800.330.7348

32

COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

Cohen & Steers Privacy Policy—(Continued)

Who we are
Who is providing this notice?	Cohen & Steers Capital Management, Inc., Cohen & Steers Asia Limited, Cohen & Steers Japan, LLC, Cohen & Steers UK Limited, Cohen & Steers Securities, LLC, Cohen & Steers Private Funds and Cohen & Steers Open and Closed-End Funds (collectively, Cohen & Steers).
What we do
How does Cohen & Steers protect my personal information?	To protect your personal information from unauthorized access and use, we use security measures that comply with federal law. These measures include computer safeguards and secured files and buildings. We restrict access to your information to those employees who need it to perform their jobs, and also require companies that provide services on our behalf to protect your information.
How does Cohen & Steers collect my personal information?	We collect your personal information, for example, when you: • Open an account or buy securities from us • Provide account information or give us your contact information • Make deposits or withdrawals from your account We also collect your personal information from other companies.
Why can’t I limit all sharing?	Federal law gives you the right to limit only: • sharing for affiliates’ everyday business purposes—information about your creditworthiness • affiliates from using your information to market to you • sharing for non-affiliates to market to you State law and individual companies may give you additional rights to limit sharing.
Definitions
Affiliates	Companies related by common ownership or control. They can be financial and nonfinancial companies. • Cohen & Steers does not share with affiliates.
Non-affiliates	Companies not related by common ownership or control. They can be financial and nonfinancial companies. • Cohen & Steers does not share with non-affiliates.
Joint marketing	A formal agreement between non-affiliated financial companies that together market financial products or services to you. • Cohen & Steers does not jointly market.

33

COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

Cohen & Steers Open-End Mutual Funds

COHEN & STEERS REALTY SHARES

• Designed for investors seeking total return, investing primarily in U.S. real estate securities

• Symbols: CSJAX, CSJCX, CSJIX, CSRSX, CSJRX, CSJZX

COHEN & STEERS REAL ESTATE SECURITIES FUND

• Designed for investors seeking total return, investing primarily in U.S. real estate securities

• Symbols: CSEIX, CSCIX, CREFX, CSDIX, CIRRX, CSZIX

COHEN & STEERS INSTITUTIONAL REALTY SHARES

• Designed for institutional investors seeking total return, investing primarily in U.S. real estate securities

• Symbol: CSRIX

COHEN & STEERS GLOBAL REALTY SHARES

• Designed for investors seeking total return, investing primarily in global real estate equity securities

• Symbols: CSFAX, CSFCX, CSSPX, GRSRX, CSFZX

COHEN & STEERS INTERNATIONAL REALTY FUND

• Designed for investors seeking total return, investing primarily in international (non-U.S.) real estate securities

• Symbols: IRFAX, IRFCX, IRFIX, IRFRX, IRFZX

COHEN & STEERS REAL ASSETS FUND

• Designed for investors seeking total return and the maximization of real returns during inflationary environments by investing primarily in real assets

• Symbols: RAPAX, RAPCX, RAPIX, RAPRX, RAPZX

COHEN & STEERS PREFERRED SECURITIES AND INCOME FUND

• Designed for investors seeking total return (high current income and capital appreciation), investing primarily in preferred and debt securities issued by U.S. and non-U.S. companies

• Symbols: CPXAX, CPXCX, CPXFX, CPXIX, CPRRX, CPXZX

COHEN & STEERS LOW DURATION PREFERRED AND INCOME FUND

• Designed for investors seeking high current income and capital preservation by investing in low-duration preferred and other income securities issued by U.S. and non-U.S. companies

• Symbols: LPXAX, LPXCX, LPXIX, LPXRX, LPXZX

COHEN & STEERS MLP & ENERGY OPPORTUNITY FUND

• Designed for investors seeking total return, investing primarily in midstream energy master limited partnership (MLP) units and related stocks

• Symbols: MLOAX, MLOCX, MLOIX, MLORX, MLOZX

COHEN & STEERS GLOBAL INFRASTRUCTURE FUND

• Designed for investors seeking total return, investing primarily in global infrastructure securities

• Symbols: CSUAX, CSUCX, CSUIX, CSURX, CSUZX

COHEN & STEERS ALTERNATIVE INCOME FUND (FORMERLY COHEN & STEERS DIVIDEND VALUE FUND)

• Designed for investors seeking high current income and capital appreciation, investing in equity, preferred and debt securities, focused on real assets and alternative income strategies

• Symbols: DVFAX, DVFCX, DVFIX, DVFRX, DVFZX

Distributed by Cohen & Steers Securities, LLC.

Please consider the investment objectives, risks, charges and expenses of any Cohen & Steers U.S. registered open-end fund carefully before investing. A summary prospectus and prospectus containing this and other information can be obtained by calling 800-330-7348 or by visiting cohenandsteers.com. Please read the summary prospectus and prospectus carefully before investing.

34

COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

OFFICERS AND DIRECTORS

Robert H. Steers

Director and Chairman

Joseph M. Harvey

Director and Vice President

Michael G. Clark

Director

George Grossman

Director

Dean A. Junkans

Director

Gerald J. Maginnis

Director

Jane F. Magpiong

Director

Daphne L. Richards

Director

C. Edward Ward, Jr.

Director

Adam M. Derechin

President and Chief Executive Officer

James Giallanza

Chief Financial Officer

Lisa D. Phelan

Chief Compliance Officer

Dana A. DeVivo

Secretary and Chief Legal Officer

Albert Laskaj

Treasurer

Stephen Murphy

Vice President

Thomas N. Bohjalian

Vice President

Jon Cheigh

Vice President

Jason A. Yablon

Vice President

KEY INFORMATION

Investment Manager and Administrator

Cohen & Steers Capital Management, Inc

280 Park Avenue

New York, NY 10017

(212) 832-3232

Co-administrator and Custodian

State Street Bank and Trust Company

One Lincoln Street

Boston, MA 02111

Transfer Agent

DST Asset Manager Solutions, Inc.

P.O. Box 219953

Kansas City, MO 64121-9953

(800) 437-9912

Legal Counsel

Ropes & Gray LLP

1211 Avenue of the Americas

New York, NY 10036

Distributor

Cohen & Steers Securities, LLC

280 Park Avenue

New York, NY 10017

NASDAQ Symbol: CSRIX

Website: cohenandsteers.com

This report is authorized for delivery only to shareholders of Cohen & Steers Institutional Realty Shares, Inc. unless accompanied or preceded by the delivery of a currently effective prospectus setting forth details of the Fund. Performance data quoted represent past performance. Past performance is no guarantee of future results and your investment may be worth more or less at the time you sell your shares.

35

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Cohen & Steers

Institutional

Realty Shares

Annual Report December 31, 2019

Beginning on January 1, 2021, as permitted by regulations adopted by the U.S. Securities and Exchange Commission, paper copies of the Fund’s annual and semi-annual shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports. Instead, the reports will be made available on the Fund’s website at www.cohenandsteers.com, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

If you have already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive shareholder reports and other communications from a Fund electronically anytime by contacting your financial intermediary or, if you are a direct investor, by signing up at www.cohenandsteers.com.

You may elect to receive all future reports in paper, free of charge, at any time. If you invest through a financial intermediary, you can contact your financial intermediary or, if you are a direct investor, you can call (800) 330-7348 to let the Fund know you wish to continue receiving paper copies of your shareholder reports. Your election to receive reports in paper will apply to all Funds held in your account if you invest through your financial intermediary or all Funds held within the fund complex if you invest directly with the Fund.

CSRIXAR

Item 2. Code of Ethics.

The registrant has adopted an Amended and Restated Code of Ethics that applies to its Principal Executive Officer and Principal Financial Officer. The Code of Ethics was in effect during the reporting period. The registrant has not amended the Code of Ethics as described in Form N-CSR during the reporting period. The registrant has not granted any waiver, including an implicit waiver, from a provision of the Code of Ethics as described in Form N-CSR during the reporting period. A current copy of the Code of Ethics is available on the registrant website at https://www.cohenandsteers.com/assets/content/uploads/Code_of_Ethics_for_Principal_Executive_and_Principal_Financial_Officers_of_the_Funds.pdf. Upon request, a copy of the Code of Ethics can be obtained free of charge by calling 800-330-7348 or writing to the Secretary of the Registrant, 280 Park Avenue, 10th floor, New York, NY 10017.

Item 3. Audit Committee Financial Expert.

The registrant’s board has determined that Gerald J. Maginnis qualifies as an audit committee financial expert based on his years of experience in the public accounting profession. The registrant’s board has determined that Michael G. Clark qualifies as an audit committee financial expert based on his years of experience in the public accounting profession and the investment management and financial services industry. Each of Messrs. Clark and Maginnis is a member of the board’s audit committee, and each is independent as such term is defined in Form N-CSR.

Item 4. Principal Accountant Fees and Services.

(a) – (d) Aggregate fees billed to the registrant for the last two fiscal years ended December 31, 2019 and December 31, 2018 for professional services rendered by the registrant’s principal accountant were as follows:

	2019	2018
Audit Fees	$42,340	$41,710
Audit-Related Fees	$0	$0
Tax Fees	$5,750	$5,660
All Other Fees	$0	$0

Tax fees were billed in connection with tax compliance services, including the preparation and review of federal and state tax returns.    

(e)(1) The audit committee is required to pre-approve audit and non-audit services performed for the registrant by the principal accountant. The audit committee also is required to pre-approve non-audit services performed by the registrant’s principal accountant for the registrant’s investment advisor and any sub-advisor (not including any sub-advisor whose role is primarily portfolio management and is subcontracted with or overseen by another investment advisor) and/or to any entity controlling, controlled by or under common control with the registrant’s investment advisor that provides ongoing services to the registrant, if the engagement for services relates directly to the operations and financial reporting of the registrant.

The audit committee may delegate pre-approval authority to one or more of its members who are independent members of the board of directors of the registrant. The member or members to whom such authority is delegated shall report any pre-approval decisions to the audit committee at its next scheduled meeting. The audit committee may not delegate its responsibility to pre-approve services to be performed by the registrant’s principal accountant to the investment advisor.

(e)(2) No services included in (b) – (d) above were approved by the audit committee pursuant to paragraphs (c)(7)(i)(C) of Rule 2-01 of Regulation S-X.

(f) Not applicable.

(g) For the fiscal years ended December 31, 2019 and December 31, 2018, the aggregate fees billed by the registrant’s principal accountant for non-audit services rendered to the registrant and for non-audit services rendered to the registrant’s investment advisor (not including any sub-advisor whose role is primarily portfolio management and is subcontracted with or overseen by another investment advisor) and/or to any entity controlling, controlled by or under common control with the registrant’s investment advisor that provides ongoing services to the registrant were:

	2019	2018
Registrant	$5,750	$5,660
Investment Advisor	$0	$0

(h) The registrant’s audit committee considered whether the provision of non-audit services that were rendered to the registrant’s investment advisor (not including any sub-advisor whose role is primarily portfolio management and is subcontracted with or overseen by another investment advisor) and/or to any entity controlling, controlled by or under common control with the registrant’s investment advisor that provides ongoing services to the registrant that were not required to be pre-approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X was compatible with maintaining the principal accountant’s independence.

Item 5. Audit Committee of Listed Registrants.

Not applicable.

Item 6. Schedule of Investments.

Included in Item 1 above.

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies.

Not applicable.

Item 8. Portfolio Managers of Closed-End Investment Companies.

Not applicable.

Item 9. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers.

Not applicable.

Item 10. Submission of Matters to a Vote of Security Holders.

None.

Item 11. Controls and Procedures.

(a) The registrant’s principal executive officer and principal financial officer have concluded that the registrant’s disclosure controls and procedures are reasonably designed to ensure that information required to be disclosed by the registrant in this Form N-CSR was recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission’s rules and forms, based upon such officers’ evaluation of these controls and procedures as of a date within 90 days of the filing date of this report.

(b) There were no changes in the registrant’s internal control over financial reporting that occurred during the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Disclosure of Securities Lending Activities for Closed-End Management Investment Companies.

Not applicable.

Item 13. Exhibits.

(a)(1) Not applicable.

(a)(2) Certifications of principal executive officer and principal financial officer as required by Rule 30a-2(a) under the Investment Company Act of 1940.

(a)(3) Not applicable.

(a)(4) Not applicable.

(b) Certifications of chief executive officer and chief financial officer as required by Rule 30a- 2(b) under the Investment Company Act of 1940.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

COHEN & STEERS INSTITUTIONAL REALTY SHARES, INC.

By:	/s/ Adam M. Derechin
	Name:   Adam M. Derechin Title:    Principal Executive Officer          (President and Chief Executive Officer)
Date:	March 2, 2020

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By:	/s/ Adam M. Derechin
	Name:   Adam M. Derechin Title:    Principal Executive Officer          (President and Chief Executive Officer)
By:	/s/ James Giallanza
	Name:   James Giallanza Title:    Principal Financial Officer          (Chief Financial Officer)
Date: March 2, 2020