# QUANTUM SI INC (QSI)

> Institutional ownership reported to the SEC as of Q3 2026, from Form 13F filings. Source: https://holderbook.com/stocks/QSI/

- Reporting holders: 4
- Reported value: $77.4K
- Held through calls: 0.0%
- Held through puts: 0.0%

A 13F reports long US equity positions only. Shorts, bonds, foreign listings and cash are not visible here, and positions are disclosed up to 45 days after the quarter ends.

## Largest holders

| Manager | Value | Shares | Share of their book | Quarters held |
|---|---|---|---|---|
| [Green Alpha Advisors, LLC](https://holderbook.com/funds/1439207-green-alpha-advisors-llc/) | $50.7K | 47,397 | 0.0% | 13 |
| [DLK Investment Management, LLC](https://holderbook.com/funds/2016793-dlk-investment-management-llc/) | $25.4K | 23,727 | 0.0% | 3 |
| [Bangor Savings Bank](https://holderbook.com/funds/1352675-bangor-savings-bank/) | $1.1K | 1,000 | 0.0% | 3 |
| [GAMMA Investing LLC](https://holderbook.com/funds/2010235-gamma-investing-llc/) | $181 | 169 | 0.0% | 4 |

## Quarter by quarter

| Quarter | Holders | Reported value |
|---|---|---|
| Q3 2026 | 4 | $77.4K |
| Q2 2026 | 142 | $50.3M |
| Q1 2026 | 156 | $50.6M |
| Q4 2025 | 138 | $78.1M |
| Q3 2025 | 124 | $98.0M |
| Q2 2025 | 135 | $132.7M |
| Q1 2025 | 139 | $72.7M |
| Q4 2024 | 124 | $152.7M |
| Q3 2024 | 107 | $46.2M |
| Q2 2024 | 100 | $56.7M |
| Q1 2024 | 97 | $106.3M |
| Q4 2023 | 92 | $115.6M |