X0508 4 2025-03-12 0001816431 Quantum-Si Inc QSI 0002032947 Vieceli John S. C/O QUANTUM-SI INCORPORATED 29 BUSINESS PARK DRIVE BRANFORD CT 06405 true Chief Product Officer false Class A Common Stock 2025-03-12 4 A 0 708333 0 A 868826 D The grant consists of restricted stock units ("RSUs"). Each RSU represents the right to receive one share of common stock upon vesting. The RSUs vest shall vest in 16 equal quarterly installments beginning on June 20, 2025 until fully vested, subject to continued service through the applicable vesting date. /s/ Christian LaPointe, Ph.D., Attorney-in-Fact. 2025-03-14