QUANTUM SI INC

Ticker: QSI CUSIP: 74765K105 Class: Common Stock

GROUP ONE TRADING, L.P.'s Holding History (CIK: 0000932540)

Note: Option positions (PUT/CALL) are excluded.

Q4 2025

Shares 245,801 Value ($000) $270 Avg Close $1.63 Range $1.07 - $3.10

Q3 2025

Shares 377,774 Value ($000) $533 Avg Close $1.45 Range $0.95 - $2.18

Q2 2025

Shares 134,632 Value ($000) $264 Avg Close $1.48 Range $1.02 - $2.15

Q2 2023

Shares 3,154 Value ($000) $6 Avg Close $1.57 Range $1.36 - $1.94

Q1 2023

Shares 1,554 Value ($000) $3 Avg Close $1.97 Range $1.54 - $2.63

Q2 2021

Shares 27,500 Value ($000) $337 Avg Close $10.48 Range $7.85 - $13.23

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2025	245,801	$270	$1.63	$1.07 - $3.10
Q3 2025	377,774	$533	$1.45	$0.95 - $2.18
Q2 2025	134,632	$264	$1.48	$1.02 - $2.15
Q2 2023	3,154	$6	$1.57	$1.36 - $1.94
Q1 2023	1,554	$3	$1.97	$1.54 - $2.63
Q2 2021	27,500	$337	$10.48	$7.85 - $13.23