QUANTERIX CORP

Ticker: QTRX CUSIP: 74766Q101 Class: Common Stock

WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC's Holding History (CIK: 0001644956)

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

Q4 2025

Shares 2,046,449 Value ($000) $13,015 Avg Close $6.21 Range $4.50 - $7.88

Q3 2025

Shares 1,315,280 Value ($000) $7,142 Avg Close $5.32 Range $4.15 - $7.09

Q2 2025

Shares 1,127,981 Value ($000) $7,501 Avg Close $5.57 Range $4.05 - $7.03

Q1 2025

Shares 1,106,063 Value ($000) $7,200 Avg Close $8.34 Range $6.16 - $12.41

Q4 2024

Shares 1,062,105 Value ($000) $11,290 Avg Close $12.16 Range $9.87 - $15.67

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2025	2,046,449	$13,015	$6.21	$4.50 - $7.88
Q3 2025	1,315,280	$7,142	$5.32	$4.15 - $7.09
Q2 2025	1,127,981	$7,501	$5.57	$4.05 - $7.03
Q1 2025	1,106,063	$7,200	$8.34	$6.16 - $12.41
Q4 2024	1,062,105	$11,290	$12.16	$9.87 - $15.67