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Table of Contents ( Mark One ) UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Minnesota ( State or other jurisdiction of incorporation or organization ) FORM 10 - K to 5540 Pioneer Creek Drive Maple Plain , Minnesota ( Address of principal executive offices ) Title of each class Common Stock , Par Value $ 0.001 Per Share or Commission File Number : 001-35435 Proto Labs , Inc. ( Exact name of Registrant as specified in its charter ) 41-1939628 ( I.R.S. Employer Identification No. ) ( 763 ) 479-3680 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) PRLB Securities registered pursuant to Section 12 ( g ) of the Act : None 55359 ( Zip Code ) Name of each exchange on which registered New York Stock Exchange Indicate by check mark if the Registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes > No Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes □ No Indicate by check mark whether the Registrant ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the Registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes > No Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T during the preceding 12 months ( or for such shorter period that the Registrant was required to submit such files ) . Yes No