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Who owns Quantum-Si (QSI) stock

129 funds reported Quantum-Si (QSI) shares in their latest 13F filings, worth $57.1M in all. The largest holder is Vanguard Group ($10.6M). Last quarter 60 funds added to their stakes and 84 cut them.

Largest holders of QSI (13F)Largest holders of QSI (13F)Vanguard Group$10.6MVanguard Capital Management LLC$6.7MARK Investment Management LLC$6.3MBlackRock$4.6MNikko Asset Management Americas$3.5MSumitomo Mitsui Trust Group$3.4MMillennium Management LLC$2.8MUBS Group AG$2.3MAQR Capital Management LLC$2.1MGeode Capital Management, LLC$2.0M

Largest holders (13F)

FundSharesValueChangeQuarter
Vanguard Group9,607,022$10.6Mincrease2025-12-31
Vanguard Capital Management LLC7,578,208$6.7Mincrease2026-06-30
ARK Investment Management LLC7,167,738$6.3Mincrease2026-06-30
BlackRock5,225,352$4.6Mdecrease2026-06-30
Nikko Asset Management Americas3,885,230$3.5Mdecrease2026-06-30
Sumitomo Mitsui Trust Group3,885,230$3.4Mdecrease2026-06-30
Millennium Management LLC3,131,726$2.8Mnew2026-06-30
UBS Group AG2,561,897$2.3Mincrease2026-06-30
AQR Capital Management LLC2,348,665$2.1Mdecrease2026-06-30
Geode Capital Management, LLC2,236,526$2.0Mdecrease2026-06-30
Jane Street Group, LLC2,142,735$1.9Mnew2026-06-30
Susquehanna International Group, LLP1,116,750$988Kdecrease2026-06-30
Vanguard Fiduciary Trust1,116,683$988Kdecrease2026-06-30
State Street890,741$788Kdecrease2026-06-30
Fosun International743,935$658Kunchanged2026-06-30

Quantum-Si's latest quarter

Quantum-Si, Q3 2026: revenue $212K (-62% year over year), net loss $22.3M, operating cash flow −$20.5M. The chart follows the revenue to costs, profit and cash.

Questions

Who owns the most QSI stock?

By the latest 13F filings: Vanguard Group ($10.6M); Vanguard Capital Management LLC ($6.7M); ARK Investment Management LLC ($6.3M); BlackRock ($4.6M); Nikko Asset Management Americas ($3.5M).

What is the short interest in QSI?

13,207,743 shares were sold short at the 2026-10-15 settlement, 11.64% of the float.

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Updated Nov 8, 2026. Read automatically from SEC filings and public data; errors are possible. Not investment advice.