X0508 4 2023-09-25 0001816431 Quantum-Si Inc QSI 0001994864 Jafri Amir C/O QUANTUM-SI INCORPORATED 29 BUSINESS PARK DR. BRANFORD CT 06405 true false Class A Common Stock 2023-09-25 4 A 0 115942 0 A 115942 D Consists of restricted stock units ("RSUs"). Each RSU represents the right to receive one share of common stock upon vesting. The RSUs vest in equal annual installments over three years beginning on September 25, 2024, subject to Mr. Jafri's continued service through the applicable vesting date. /s/ Christian LaPointe, Ph.D., Attorney-in-Fact 2023-09-26