X0508 4/A 2025-11-25 2025-11-26 0 0001443669 Proto Labs Inc PRLB 0001870293 Kenison Michael R. 5540 PIONEER CREEK DRIVE MAPLE PLAIN MN 55359 0 1 0 0 Chief Operations Officer 1 Common Stock 2025-11-25 4 M 0 3048 33.84 A 31946 D Common Stock 2025-11-25 4 S 0 3048 50.1741 D 28898 D Employee Stock Option (right to buy) 33.84 2025-11-25 4 M 0 3048 0 D 2026-02-14 Common Stock 3048 0 D Includes 57 shares of Common Stock of the issuer purchased on November 15, 2025 through the issuer's Employee Stock Purchase Plan program. These shares were acquired and sold pursuant to Reporting Person's 10b5-1 plan adopted August 15, 2025. Reflects the weighted average price of 3,048 shares of Common Stock of the issuer sold by the Reporting Person in multiple transactions on November 25, 2025 with sale prices ranging from $50.00 to $50.53 per share. The Reporting Person undertakes to provide upon request by U.S. Securities and Exchange Commission staff, the issuer, or a securityholder of the issuer full information regarding the number of shares sold at each separate price. Fully vested. This amendment reflects an adjustment to the expiration date of the Employee Stock Options to correct a clerical error in the reporting person's Form 4 filed on November 25, 2025. All transaction details were accurately reported on the original Form 4. /s/ Kareem S. Tawfic, Attorney-in-Fact 2025-12-03