Proto Labs Inc — Director's Dealing 2013

Jan 17, 2013

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Proto Labs Inc (PRLB)
CIK: 0001443669
Period of Report: 2013-01-16

Reporting Person: Dietrick William M. (Vice President of Marketing)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2013-01-16	Common Stock	M	20000	$5.00	Acquired	21250	Direct
2013-01-16	Common Stock	M	12000	$7.86	Acquired	33250	Direct
2013-01-16	Common Stock	S	32000	$42.3015	Disposed	1250	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2013-01-16	Employee Stock Option (right to buy)	$5.00	M	20000	Disposed	2018-05-12	Common Stock (20000)	Direct
2013-01-16	Employee Stock Option (right to buy)	$7.86	M	12000	Disposed	2020-12-21	Common Stock (12000)	Direct

Footnotes

F1: Transaction effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on July 27, 2012. The transactions reported on this Form 4 conclude the transactions contemplated by the reporting person's Rule 10b5-1 trading plan.

F2: Includes 1,250 shares acquired under the issuers's employee stock purchase plan on November 16, 2012.

F3: Reflects the weighted average price of 32,000 shares of common stock of Proto Labs, Inc. sold by the reporting person in multiple transactions on January 16, 2013 with sale prices ranging from $42.00 to $42.67 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.

F4: The option vests as to 20% of the shares in five annual installments beginning on May 12, 2009.

F5: The option vests as to 20% of the shares in five annual installments beginning on December 21, 2011.