Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in OS held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | VANGUARD PORTFOLIO MANAGEMENT LLC | 4.9M | $117.6M | β | 4.910% | 0.01% |
| 2 | Temasek Holdings (Private) Ltd | 4.3M | $102.4M | 0.0% | 4.275% | 0.34% |
| 3 | FIL Ltd | 4.0M | $95.8M | β | 4.000% | 0.07% |
| 4 | VANGUARD CAPITAL MANAGEMENT LLC | 3.9M | $93.2M | β | 3.890% | 0.00% |
| 5 | CNH PARTNERS LLC | 3.4M | $81.4M | β | 3.400% | 1.34% |
| 6 | HIGHLAND CAPITAL MANAGEMENT FUND ADVISORS, L.P. | 3.4M | $80.6M | β | 3.365% | 5.53% |
| 7 | O'Connor Alternative Investments LLC | 3.2M | $76.5M | β | 3.193% | 6.56% |
| 8 | Polar Asset Management Partners Inc. | 2.9M | $70.7M | β | 2.950% | 1.57% |
| 9 | MILLENNIUM MANAGEMENT LLC | 2.5M | $59.3M | +636.4% | 2.476% | 0.04% |
| 10 | BlackRock, Inc. | 2.3M | $56.1M | +11.1% | 2.344% | 0.00% |
| 11 | UBS Group AG | 2.3M | $54.2M | +372.4% | 2.261% | 0.01% |
| 12 | Man Group plc | 2.2M | $52.9M | β | 2.209% | 0.10% |
| 13 | GOLDMAN SACHS GROUP INC | 2.0M | $47.7M | +182.0% | 1.990% | 0.01% |
| 14 | CITADEL ADVISORS LLC | 1.9M | $45.9M | -19.1% | 1.917% | 0.02% |
| 15 | Pentwater Capital Management LP | 1.9M | $45.4M | β | 1.894% | 0.24% |
| 16 | Vivaldi Asset Management, LLC | 1.8M | $44.2M | β | 1.846% | 2.32% |
| 17 | SOROS FUND MANAGEMENT LLC | 1.8M | $43.9M | +454.6% | 1.834% | 0.52% |
| 18 | TIG Advisors, LLC | 1.7M | $41.7M | β | 1.742% | 2.14% |
| 19 | MORGAN STANLEY | 1.7M | $39.6M | +75.4% | 1.654% | 0.00% |
| 20 | HSBC HOLDINGS PLC | 1.6M | $38.3M | β | 1.599% | 0.02% |
| 21 | ODDO BHF ASSET MANAGEMENT SAS | 1.4M | $34.8M | β | 1.453% | 1.37% |
| 22 | HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND | 1.2M | $29.6M | +105.8% | 1.237% | 0.05% |
| 23 | ALLIANCEBERNSTEIN L.P. | 1.5M | $28.2M | β | 1.538% | 0.01% |
| 24 | Qube Research & Technologies Ltd | 1.1M | $27.2M | +49.2% | 1.135% | 0.03% |
| 25 | CITIGROUP INC | 1.1M | $26.5M | +295.3% | 1.106% | 0.01% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). β% of Fundβ shows how much of that investorβs total 13F portfolio is invested in OS β a direct measure of their conviction.
Filings activity in OS during Q1 2026, grouped by how each filer changed its position.
Institutions that opened a new OS position in Q1 2026
Institutions that fully closed their OS position in Q1 2026
7 quarters of 13F filings Β· Ξ columns show change vs prior quarter
| Quarter | Inst. Holders | Ξ Holders | Ownership % | Ξ Ownership | Total 13F Value | Ξ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 174 | 2.8% | 81.90% | +23.70 pp | $1.96B | +41% |
| Q4 2025 | 179 | +0.6% | 58.20% | +5.35 pp | $1.39B | +10% |
| Q3 2025 | 178 | 4.3% | 52.85% | 39.25 pp | $1.27B | 43% |
| Q2 2025 | 186 | +35% | 92.10% | +44.37 pp | $2.21B | +93% |
| Q1 2025 | 138 | 13% | 47.73% | 8.57 pp | $1.14B | 15% |
| Q4 2024 | 159 | +45% | 56.30% | 133.34 pp | $1.35B | 70% |
| Q3 2024 | 110 | β | 189.64% | β | $4.54B | β |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Ξ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying OS stock.
Based on Q1 2026 13F filings, institutional ownership of OneStream, Inc. Class A Common Stock stands at 81.9%, held across 174 reporting institutions.
VANGUARD PORTFOLIO MANAGEMENT LLC is the largest reported institutional holder of OS, with approximately 4,900,450 shares worth $0.12B as of Q1 2026.
Yes β 3 widely-followed marquee investors appear among the top 25 institutional holders of OS, including MILLENNIUM MANAGEMENT LLC, CITADEL ADVISORS LLC, SOROS FUND MANAGEMENT LLC.
Our composite Smart Money Score for OS is 67 out of 100 (Bullish). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
84 institutions opened new positions in OS during Q1 2026, while 89 fully exited. 67 added to existing positions and 23 trimmed.
OS institutional ownership rose by 23.70 percentage points quarter-over-quarter, with a net change of -5 holders.
The top 10 institutions account for 42.5% of all reported 13F value in OS, and the top 25 account for 73.1%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
OneStream, Inc. Class A Common Stock (OS) Institutional Ownership