Quanterix (QTRX) investor relations material

Executive summary

• The annual meeting is scheduled for June 9, 2026, and will be held virtually for shareholder participation.

• The proxy supplement updates Proposal No. 4 regarding amendments to the 2017 Equity Incentive Plan, reinstating and adding award limitations.

• All other information in the original proxy statement remains unchanged except as updated by this supplement.

Voting matters and shareholder proposals

• Shareholders will vote on the election of directors, executive compensation (say-on-pay), ratification of KPMG LLP as auditor, and approval of the amended 2017 Equity Incentive Plan.

• Proposal No. 4 amends the 2017 Plan to reinstate a per-participant annual share award limit and adds a cap on non-employee director compensation.

• Proxy cards already submitted remain valid; no new cards are required due to the supplement.

Board of directors and corporate governance

• The Board recommends voting FOR all director nominees and FOR all proposals.

• The Board delegated authority to officers and the Compensation Committee Chair to approve amendments to the equity plan.