Proto Labs (NYSE: PRLB) COO executes 10b5-1 option exercises and small share sale

Rhea-AI Filing Summary

Proto Labs Inc Chief Operations Officer Michael R. Kenison reported an exercise-and-sell transaction in company stock. On May 7, 2026, he sold 200 shares of Common Stock at $70.00 per share in an open-market sale and exercised stock options to acquire 200 shares at strike prices of $33.52 and $33.84 per share.

The filing shows these trades were made under a pre-arranged 10b5-1 trading plan adopted on August 15, 2025. Following the transactions, he holds 27,186 Common Stock shares directly and continues to hold employee stock options, including grants with remaining balances of 7,455 and 7,612 options that vest annually starting on specified February 13 vesting dates.

Insights

Equity compensation and insider-trading analyst

Routine option exercises paired with a small pre-planned sale.

Chief Operations Officer Michael R. Kenison exercised employee stock options for 200 Proto Labs shares at strike prices of $33.52 and $33.84, then sold 200 shares at $70.00 on May 7, 2026. This pattern reflects a classic exercise-and-sell event.

A key detail is the footnote stating the trades occurred under a 10b5-1 plan adopted on August 15, 2025, indicating they were pre-scheduled rather than opportunistic. After these transactions, he still directly owns 27,186 shares and retains option positions of 7,455 and 7,612 options tied to awards that vest in annual February 13 installments, suggesting ongoing long-term equity exposure.

Insider Trade Summary 10b5-1

Net Seller: 200 shares ($14,000)

Net Sell 5 txns

Insider Kenison Michael R.

Role Chief Operations Officer

Sold 200 shs ($14K)

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (right to buy)	100	$0.00	--
Exercise	Employee Stock Option (right to buy)	100	$0.00	--
Exercise	Common Stock	100	$33.84	$3K
Exercise	Common Stock	100	$33.52	$3K
Sale	Common Stock	200	$70.00	$14K

Holdings After Transaction: Employee Stock Option (right to buy) — 7,612 shares (Direct, null); Common Stock — 27,286 shares (Direct, null)

Footnotes (1)

1. These shares were acquired and sold pursuant to Reporting Person's 10b5-1 plan adopted August 15, 2025. 25% of shares subject to the award will vest on February 13, 2024, and on each February 13th thereafter until all shares subject to the award are fully vested. 25% of shares subject to the award will vest on February 13, 2025, and on each February 13th thereafter until all shares subject to the award are fully vested.

Key Figures

Shares sold: 200 shares of Common Stock Sale price: $70.00 per share Shares following transaction: 27,186 shares +4 more

7 metrics

Shares sold 200 shares of Common Stock Open-market sale on May 7, 2026 at $70.00 per share

Sale price $70.00 per share Price for 200-share Common Stock sale on May 7, 2026

Shares following transaction 27,186 shares Direct Common Stock holdings after reported transactions

Options exercised (grant 1) 100 shares at $33.52 strike Employee Stock Option exercise converting into Common Stock

Options exercised (grant 2) 100 shares at $33.84 strike Employee Stock Option exercise converting into Common Stock

Remaining options grant 1 7,455 options Employee Stock Option balance after exercise; expires February 13, 2034

Remaining options grant 2 7,612 options Employee Stock Option balance after exercise; expires February 14, 2033

Key Terms

10b5-1 plan, Employee Stock Option, open-market sale, Exercise or conversion of derivative security, +1 more

5 terms

10b5-1 plan financial

"These shares were acquired and sold pursuant to Reporting Person's 10b5-1 plan adopted August 15, 2025."

A 10b5-1 plan is a pre-arranged strategy that allows company insiders to buy or sell their shares at predetermined times and prices, even while they are aware of confidential information. It acts like a scheduled appointment for trading, helping ensure transactions happen transparently and legally, which can reassure investors that trades are not based on insider knowledge.

Employee Stock Option financial

"security_title: Employee Stock Option (right to buy)"

An employee stock option is a promise that lets a worker buy company shares later at a predetermined price, often after they stay for a certain period or meet performance goals — think of it like a coupon that locks in today's price for a future purchase. It matters to investors because options align employees’ incentives with company performance, can increase the number of shares outstanding (dilution) when exercised, and represent a compensation cost that affects reported profits and shareholder value.

open-market sale financial

"transaction_action: open-market sale"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Exercise or conversion of derivative security financial

"transaction_code_description: Exercise or conversion of derivative security"

vest financial

"25% of shares subject to the award will vest on February 13, 2024"

A vest is the process by which an employee earns the right to receive certain benefits or ownership interests, such as stock or retirement funds, over time. It’s similar to earning a reward gradually, ensuring that the benefit becomes fully yours only after a set period or meeting specific conditions. This makes it important for investors because it determines when they can actually claim or use those benefits.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Kenison Michael R.

(Last) (First) (Middle)

5540 PIONEER CREEK DRIVE

(Street)

MAPLE PLAIN MINNESOTA 55359

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Proto Labs Inc [ PRLB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Operations Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/07/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/07/2026		M(1)		100	A	$33.84	27,286	D
Common Stock	05/07/2026		M(1)		100	A	$33.52	27,386	D
Common Stock	05/07/2026		S(1)		200	D	$70	27,186	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (right to buy)	$33.84	05/07/2026		M(1)			100	(2)	02/14/2033	Common Stock	100	$0	7,612	D
Employee Stock Option (right to buy)	$33.52	05/07/2026		M(1)			100	(3)	02/13/2034	Common Stock	100	$0	7,455	D

Explanation of Responses:

1. These shares were acquired and sold pursuant to Reporting Person's 10b5-1 plan adopted August 15, 2025.

2. 25% of shares subject to the award will vest on February 13, 2024, and on each February 13th thereafter until all shares subject to the award are fully vested.

3. 25% of shares subject to the award will vest on February 13, 2025, and on each February 13th thereafter until all shares subject to the award are fully vested.

Remarks:

	/s/ W. Morgan Burns, Attorney-in-Fact	05/08/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What did Proto Labs (PRLB) COO Michael R. Kenison do in this Form 4 filing?

Michael R. Kenison exercised employee stock options for 200 Proto Labs shares and sold 200 Common Stock shares at $70.00 each. These transactions occurred on May 7, 2026 and were reported as routine equity compensation and trading activity.

How many Proto Labs (PRLB) shares did the COO sell and at what price?

The COO sold 200 Proto Labs Common Stock shares at $70.00 per share. The sale took place on May 7, 2026 and was described as an open-market or private transaction under SEC transaction code S.

How many Proto Labs (PRLB) shares does the COO hold after the reported transactions?

After the reported transactions, the COO directly holds 27,186 Proto Labs Common Stock shares. This figure reflects his position following the May 7, 2026 option exercises and the 200-share sale disclosed in the Form 4 filing.

Were the Proto Labs (PRLB) insider trades made under a Rule 10b5-1 plan?

Yes. A footnote states the shares were acquired and sold pursuant to the reporting person’s 10b5-1 trading plan adopted on August 15, 2025. Such pre-arranged plans are designed to schedule trades in advance and reduce concerns about trade timing.

What stock option activity did the Proto Labs (PRLB) COO report?

He reported exercising options for 100 shares at a $33.52 strike and 100 shares at a $33.84 strike. These were employee stock options converting into Common Stock, with related option awards continuing to vest annually on specified February 13 dates.

What employee stock option balances remain for the Proto Labs (PRLB) COO?

After the exercises, one employee stock option award shows 7,455 options outstanding and another shows 7,612 options outstanding. Footnotes explain that 25% of shares in each award vest on February 13 and then annually until fully vested.