List of institutional investors who are active in the last 9 months.
| # | Name | Latest Filing Quarter | Latest Holding Count | Latest AUM |
| 5351 | OPUS INVESTMENT MANAGEMENT INC | 2024Q4 | 29 | $135.4M |
| 5352 | ORACLE INVESTMENT MANAGEMENT INC | 2024Q4 | 13 | $148.94M |
| 5353 | ORBA Wealth Advisors L.L.C. | 2025Q1 | 103 | $186.44M |
| 5354 | ORBIMED ADVISORS LLC | 2024Q4 | 111 | $4.82B |
| 5355 | Orbis Allan Gray Ltd | 2024Q4 | 84 | $18.59B |
| 5356 | Orca Investment Management LLC | 2024Q4 | 57 | $106.33M |
| 5357 | Orca Wealth Management LLC | 2024Q4 | 62 | $110.87M |
| 5358 | Orcam Financial Group | 2024Q4 | 42 | $101.57M |
| 5359 | Orchard Capital Management LLC | 2024Q4 | 49 | $200.26M |
| 5360 | Oregon Pacific Wealth Management LLC | 2025Q1 | 115 | $91.68M |
| 5361 | OREGON PUBLIC EMPLOYEES RETIREMENT FUND | 2025Q1 | 1507 | $5.18B |
| 5362 | ORG Partners LLC | 2025Q1 | 1396 | $406.3M |
| 5363 | ORG Wealth Partners LLC | 2025Q1 | 727 | $318.1M |
| 5364 | Orgel Wealth Management LLC | 2025Q1 | 80 | $3.73B |
| 5365 | Oribel Capital Management LP | 2024Q4 | 40 | $1.47B |
| 5366 | Oriental Harbor Investment Fund | 2024Q4 | 14 | $994.79M |
| 5367 | Origin Asset Management LLP | 2024Q4 | 7 | $43.49M |
| 5368 | Orin Green Financial LLC | 2024Q4 | 77 | $205.46M |
| 5369 | Orion Capital Management LLC | 2024Q4 | 457 | $226.22M |
| 5370 | Orion Investment Co | 2024Q4 | 65 | $250.66M |
| 5371 | Orion Portfolio Solutions LLC | 2024Q4 | 1769 | $9.73B |
| 5372 | Orion Resource Partners LP | 2024Q4 | 19 | $506.99M |
| 5373 | ORIX Corp | 2024Q4 | 1 | $201.54M |
| 5374 | Orland Properties Ltd | 2024Q4 | 7 | $68.63M |
| 5375 | ORLEANS CAPITAL MANAGEMENT CORP | 2024Q4 | 92 | $177.95M |
| 5376 | ORRSTOWN FINANCIAL SERVICES INC | 2025Q1 | 129 | $420.13M |
| 5377 | ORSER CAPITAL MANAGEMENT LLC | 2025Q1 | 49 | $136.21M |
| 5378 | Orvieto Partners L.P. | 2024Q4 | 35 | $118.57M |
| 5379 | OSAIC HOLDINGS INC. | 2024Q4 | 6936 | $37.6B |
| 5380 | OSBORNE PARTNERS CAPITAL MANAGEMENT LLC | 2025Q1 | 209 | $1.69B |
| 5381 | Osprey Private Wealth LLC | 2025Q1 | 48 | $168.66M |
| 5382 | OSSIAM | 2024Q4 | 622 | $5.79B |
| 5383 | Osterweis Capital Management, Inc. | 2024Q4 | 177 | $1.67B |
| 5384 | OSTRUM ASSET MANAGEMENT | 2024Q4 | 627 | $1.15B |
| 5385 | Otter Creek Advisors LLC | 2024Q4 | 35 | $145.26M |
| 5386 | OUTFITTER FINANCIAL LLC | 2024Q4 | 81 | $124.91M |
| 5387 | Outlook Wealth Advisors LLC | 2025Q1 | 258 | $352.22M |
| 5388 | OV Management LLC | 2024Q4 | 56 | $215.38M |
| 5389 | Ovata Capital Management Ltd | 2024Q4 | 23 | $209.06M |
| 5390 | Overbrook Management Corp | 2025Q1 | 46 | $424.49M |
| 5391 | OVERSEA-CHINESE BANKING Corp Ltd | 2025Q1 | 365 | $3.41B |
| 5392 | Owen LaRue LLC | 2024Q4 | 89 | $188.28M |
| 5393 | Owl Creek Asset Management, L.P. | 2024Q4 | 17 | $425.35M |
| 5394 | Owls Nest Partners IA LLC | 2024Q4 | 16 | $450.81M |
| 5395 | Ownership Capital B.V. | 2025Q1 | 22 | $2.18B |
| 5396 | Oxbow Advisors LLC | 2025Q1 | 202 | $917.22M |
| 5397 | Oxbow Capital Management (HK) Ltd | 2024Q4 | 9 | $281.77M |
| 5398 | OxenFree Capital LLC | 2025Q1 | 42 | $131.44M |
| 5399 | OXFORD ASSET MANAGEMENT LLP | 2024Q4 | 405 | $193.16M |
| 5400 | OXFORD FINANCIAL GROUP LTD. LLC | 2024Q4 | 296 | $1.54B |