Institutional Ownership
Quantum Si Inc
CUSIP 74765K105COM CL AQSIQ1 2026
13D / 13G Filings
30
Schedule 13D/13G on record
Beneficial Filers
11
Distinct reporting persons
Largest Stake
100.0%
Max % of class reported
Institutional Holders
152
13F filers (latest quarter)
Beneficial Owners — Schedule 13D / 13G
30 filings · latest Oct 30, 2025
| # | Filed | Reporting Person | Form | % of Class | Shares | Filing |
|---|---|---|---|---|---|---|
| 1 | Oct 30, 2025 | The Vanguard Group | 13G/A | 4.8% | 8.71M | SEC |
| 2 | Sep 11, 2025 | Rothberg Jonathan M | 13D/A | 100.0% | — | SEC |
| 3 | Jul 29, 2025 | The Vanguard Group | 13G | 5.3% | 8.67M | SEC |
| 4 | Jun 6, 2025 | Ark Investment Management LLC | 13G/A | 4.8% | 7.81M | SEC |
| 5 | May 14, 2025 | Ark Investment Management LLC | 13G/A | 5.3% | 8.71M | SEC |
| 6 | Feb 14, 2025 | Ark Investment Management LLC | 13G/A | 7.2% | 8.85M | SEC |
| 7 | Feb 13, 2025 | Nikko Asset Management Americas, Inc. | 13G/A | 4.8% | 5.97M | SEC |
| 8 | Feb 4, 2025 | Sumitomo Mitsui Trust Group, Inc. | 13G/A | 4.8% | 5.97M | SEC |
| 9 | Jan 10, 2025 | Ark Investment Management LLC | 13G/A | 9.7% | 11.84M | SEC |
| 10 | Dec 31, 2024 | Rothberg Jonathan M | 13D/A | 100.0% | — | SEC |
20 more beneficial-ownership filings on Premium
See the full Schedule 13D/13G history for Quantum Si Inc.
Unlock full historyTop Institutional Holders (13F)
Largest reported positions · latest quarter
| # | Fund | Shares | Value |
|---|---|---|---|
| 1 | Blackrock, Inc. | 13.41M | $10.38M |
| 2 | Ark Investment Management LLC | 6.88M | $5.32M |
| 3 | Amova Asset Management Americas, Inc. | 4.39M | $3.43M |
| 4 | Sumitomo Mitsui Trust Group, Inc. | 4.39M | $3.40M |
| 5 | Geode Capital Management, LLC | 3.84M | $2.97M |
| 6 | State Street Corp | 3.77M | $2.92M |
| 7 | Aqr Capital Management LLC | 2.39M | $1.85M |
| 8 | Ubs Group AG | 1.70M | $1.32M |
| 9 | Susquehanna International Group, LLP | 1.46M | $1.13M |
| 10 | Northern Trust Corp | 1.26M | $975.8K |