Vieceli John S. 4

What Happened
John S. Vieceli, Chief Product Officer at Quantum‑Si (QSI), sold a total of 30,223 shares in two open‑market transactions tied to the vesting of previously granted restricted stock units (RSUs). On 2026‑06‑22 he sold 15,111 shares at an average price of $0.96 for proceeds of $14,467, and on 2026‑06‑23 he sold 15,112 shares at an average price of $0.90 for proceeds of $13,586. Combined proceeds were approximately $28,053. These sales were made pursuant to a mandatory sell‑to‑cover provision to satisfy tax withholding on vested RSUs, not voluntary disposition signaling.

Key Details

• Transaction dates and reported prices:
  • 2026‑06‑22: 15,111 shares sold, weighted average price $0.96, proceeds $14,467 (price range per footnote: $0.9212–$1.005).
  • 2026‑06‑23: 15,112 shares sold, weighted average price $0.90, proceeds $13,586 (price range per footnote: $0.88–$0.9291).
• Total shares sold: 30,223; total proceeds ≈ $28,053.
• Shares owned after transaction: Not disclosed in the excerpt of the filing provided.
• Notable footnotes: F1 — sales were mandatory sell‑to‑cover for tax withholding tied to RSU vesting (the executive cannot alter this provision). F2/F3 — weighted‑average prices reported; full per‑share breakdowns are available on request.
• Filing timeliness: Form 4 was filed 2026‑06‑24 for transactions on 6/22 and 6/23; filing appears timely (no late‑filing indication).

Context
These sales are tax‑withholding (sell‑to‑cover) transactions related to RSU vesting, which are routine and do not necessarily reflect the insider’s view of the company’s prospects. For retail investors, outright purchases by insiders tend to be more informative than routine sales for tax purposes.