X0202 SCHEDULE 13G/A 0000820027 XXXXXXXX LIVE 5 Common Stock 03/31/2026 0001503274 Quanterix Corp 74766Q101 900 Middlesex Turnpike Billerica MA 01821 Rule 13d-1(b) Ameriprise Financial, Inc. b DE 0 3542374 0 3542374 3542374 N 7.5 HC Quanterix Corp 900 Middlesex Turnpike, Billerica, MA 01821 Ameriprise Financial, Inc. ("AFI") 145 Ameriprise Financial Center, Minneapolis, MN 55474 Delaware N HC Incorporated by reference to Items (5)-(9) and (11) of the cover page pertaining to the reporting person. AFI disclaims beneficial ownership of any shares reported on this Schedule. The information required by Item 4(b) is set forth in Rows (5)-(9) and (11) of the cover page for the Reporting Person hereto and is incorporated herein by reference for the Reporting Person. The information required by Item 4(c) is set forth in Rows (5)-(9) and (11) of the cover page for the Reporting Person hereto and is incorporated herein by reference for the Reporting Person. The information required by Item 4(c) is set forth in Rows (5)-(9) and (11) of the cover page for the Reporting Person hereto and is incorporated herein by reference for the Reporting Person. The information required by Item 4(c) is set forth in Rows (5)-(9) and (11) of the cover page for the Reporting Person hereto and is incorporated herein by reference for the Reporting Person. The information required by Item 4(c) is set forth in Rows (5)-(9) and (11) of the cover page for the Reporting Person hereto and is incorporated herein by reference for the Reporting Person. Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Ameriprise Financial, Inc. /s/ Michael G. Clarke 05/15/2026 Contact Information Charles Chiesa VP Fund Treasurer Global Operations and Investor Services Telephone: 617-385-9593