There is a long list of 152 institutional holders of OPI within the last two holding periods in our database of 13F filers, so we've sorted through to present to you just the top 50 institutional holders of OPI by largest to smallest position reported in the institutional investor's latest 13F filing. In the institutional-holders-of-OPI table below, the initial column indicates the name of each top institutional holder of OPI, with a link to that fund's top holdings. The next columns indicate the amount of OPI stock held by each of the institutional holders of OPI, followed by the OPI position size held by the institution, and finally the date of the quarterly 13F filing period the holdings data represents for that institution.

Holder	Amount	Position Size ($ in 1000's)	As of
BlackRock Inc.	5,434,106	$39,778	12/31/2023
OPI	5,434,106	$39,778	12/31/2023
Vanguard Group Inc.	4,874,755	$35,683	12/31/2023
OPI	4,874,755	$35,683	12/31/2023
Invesco Ltd.	2,966,354	$21,714	12/31/2023
OPI	2,966,354	$21,714	12/31/2023
Charles Schwab Investment Management Inc.	1,964,664	$14,381	12/31/2023
OPI	1,964,664	$14,381	12/31/2023
LSV Asset Management	1,905,937	$13,951	12/31/2023
OPI	1,905,937	$13,951	12/31/2023
AQR Capital Management LLC	1,481,683	$10,846	12/31/2023
OPI	1,481,683	$10,846	12/31/2023
State Street Corp	1,369,685	$10,026	12/31/2023
OPI	1,369,685	$10,026	12/31/2023
Geode Capital Management LLC	1,253,364	$9,175	12/31/2023
OPI	1,253,364	$9,175	12/31/2023
Arrowstreet Capital Limited Partnership	866,301	$6,341	12/31/2023
OPI	866,301	$6,341	12/31/2023
Mirae Asset Global Investments Co. Ltd.	772,697	$5,656	12/31/2023
OPI	772,697	$5,656	12/31/2023
Morgan Stanley	694,462	$5,083	12/31/2023
OPI	694,462	$5,083	12/31/2023
Dimensional Fund Advisors LP	660,625	$4,836	12/31/2023
OPI	660,625	$4,836	12/31/2023
Goldman Sachs Group Inc.	606,171	$4,437	12/31/2023
OPI	606,171	$4,437	12/31/2023
Householder Group Estate & Retirement Specialist LLC	517,375	$3,787	12/31/2023
OPI	517,375	$3,787	12/31/2023
Prudential Financial Inc.	432,911	$3,169	12/31/2023
OPI	432,911	$3,169	12/31/2023
Northern Trust Corp	424,188	$3,105	12/31/2023
OPI	424,188	$3,105	12/31/2023
D. E. Shaw & Co. Inc.	388,742	$2,846	12/31/2023
OPI	388,742	$2,846	12/31/2023
Millennium Management LLC	353,491	$2,588	12/31/2023
OPI	353,491	$2,588	12/31/2023
Two Sigma Investments LP	293,520	$2,149	12/31/2023
OPI	293,520	$2,149	12/31/2023
Two Sigma Advisers LP	281,327	$2,059	12/31/2023
OPI	281,327	$2,059	12/31/2023
Bank of New York Mellon Corp	199,574	$1,461	12/31/2023
OPI	199,574	$1,461	12/31/2023
Bank of America Corp DE	184,349	$1,349	12/31/2023
OPI	184,349	$1,349	12/31/2023
UBS Group AG	176,930	$1,295	12/31/2023
OPI	176,930	$1,295	12/31/2023
Susquehanna International Group LLP		$1,286	12/31/2023
OPI	168,634	$1,234	12/31/2023
Call	123,000	$900	12/31/2023
Put	115,800	$848	12/31/2023
Nuveen Asset Management LLC	139,234	$1,019	12/31/2023
OPI	139,234	$1,019	12/31/2023
Man Group plc	126,917	$929	12/31/2023
OPI	126,917	$929	12/31/2023
JPMorgan Chase & Co.	119,479	$875	12/31/2023
OPI	119,479	$875	12/31/2023
Barclays PLC	116,838	$855	12/31/2023
OPI	116,838	$855	12/31/2023
Penserra Capital Management LLC	116,222	$850	12/31/2023
OPI	116,222	$850	12/31/2023
Connor Clark & Lunn Investment Management Ltd.	108,328	$793	12/31/2023
OPI	108,328	$793	12/31/2023
Citadel Advisors LLC		$790	12/31/2023
Call	172,900	$1,266	12/31/2023
Put	75,500	$553	12/31/2023
OPI	10,499	$77	12/31/2023
Franklin Resources Inc.	91,372	$669	12/31/2023
OPI	91,372	$669	12/31/2023
Tudor Investment Corp Et Al	88,277	$646	12/31/2023
OPI	88,277	$646	12/31/2023
Rhumbline Advisers	87,474	$640	12/31/2023
OPI	87,474	$640	12/31/2023
National Asset Management Inc.	86,588	$634	12/31/2023
OPI	86,588	$634	12/31/2023
Nisa Investment Advisors LLC	81,790	$599	12/31/2023
OPI	81,790	$599	12/31/2023
Alliancebernstein L.P.	78,309	$573	12/31/2023
OPI	78,309	$573	12/31/2023
BNP Paribas Arbitrage SA	76,889	$563	12/31/2023
OPI	76,889	$563	12/31/2023
State of Wisconsin Investment Board	76,400	$559	12/31/2023
OPI	76,400	$559	12/31/2023
Public Employees Retirement System of Ohio	75,424	$552	12/31/2023
OPI	75,424	$552	12/31/2023
Asset Management One Co. Ltd.	71,556	$536	12/31/2023
OPI	71,556	$536	12/31/2023
Algert Global LLC	65,710	$481	12/31/2023
OPI	65,710	$481	12/31/2023
Jane Street Group LLC	65,348	$478	12/31/2023
OPI	65,348	$478	12/31/2023
Principal Financial Group Inc.	53,636	$393	12/31/2023
OPI	53,636	$393	12/31/2023
Nomura Asset Management Co. Ltd.	51,800	$379	12/31/2023
OPI	51,800	$379	12/31/2023
Macquarie Group Ltd.	45,686	$334	12/31/2023
OPI	45,686	$334	12/31/2023
Alps Advisors Inc.	41,732	$305	12/31/2023
OPI	41,732	$305	12/31/2023
Los Angeles Capital Management & Equity Research Inc.	145,788	$297	03/31/2024
OPI	145,788	$297	03/31/2024
LPL Financial LLC	39,970	$293	12/31/2023
OPI	39,970	$293	12/31/2023
Arrow Investment Advisors LLC	34,567	$253	12/31/2023
OPI	34,567	$253	12/31/2023