X0306 4 2013-11-08 0 0001443669 Proto Labs Inc PRLB 0001542472 Cleveland Bradley A. 5540 PIONEER CREEK DRIVE MAPLE PLAIN MN 55359 1 1 0 0 President and CEO Common Stock 2013-11-08 4 S 0 4648 79.39 D 112720 I By Bradley A. Cleveland Declaration Trust Common Stock 2013-11-08 4 S 0 12565 80.46 D 100155 I By Bradley A. Cleveland Declaration Trust Common Stock 2013-11-08 4 S 0 7709 81.45 D 92446 I By Bradley A. Cleveland Declaration Trust Common Stock 2013-11-08 4 S 0 21115 82.68 D 71331 I By Bradley A. Cleveland Declaration Trust Common Stock 2013-11-08 4 S 0 7096 83.57 D 64235 I By Bradley A. Cleveland Declaration Trust Sales effected pursuant to Rule 10b5-1 trading plan adopted by the Bradley A. Cleveland Declaration Trust (the "Trust") on August 30, 2013. Reflects the weighted average price of 4,648 shares of common stock of Proto Labs, Inc. sold by the Trust in multiple transactions on November 8, 2013 with sale prices ranging from $78.96 to $79.92 per share. The reporting person undertakes to provide upon request by the U.S. Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. Reflects the weighted average price of 12,565 shares of common stock of Proto Labs, Inc. sold by the Trust in multiple transactions on November 8, 2013 with sale prices ranging from $79.98 to $80.94 per share. The reporting person undertakes to provide upon request by the U.S. Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. Reflects the weighted average price of 7,709 shares of common stock of Proto Labs, Inc. sold by the Trust in multiple transactions on November 8, 2013 with sale prices ranging from $81.00 to $81.92 per share. The reporting person undertakes to provide upon request by the U.S. Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. Reflects the weighted average price of 21,115 shares of common stock of Proto Labs, Inc. sold by the Trust in multiple transactions on November 8, 2013 with sale prices ranging from $82.08 to $83.07 per share. The reporting person undertakes to provide upon request by the U.S. Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. Reflects the weighted average price of 7,096 shares of common stock of Proto Labs, Inc. sold by the Trust in multiple transactions on November 8, 2013 with sale prices ranging from $83.15 to $83.74 per share. The reporting person undertakes to provide upon request by the U.S. Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. /s/ Mark D. Pihlstrom, attorney-in-fact for Bradley A. Cleveland 2013-11-12