Disciplined Growth Investors (PRLB) discloses 10% Proto Labs ownership stake

Rhea-AI Filing Summary

Disciplined Growth Investors, Inc. reports its ownership position in Proto Labs Inc common stock. The firm beneficially owns 2,380,514 shares of Proto Labs common stock, representing 10.0% of the class as of June 30, 2026.

Disciplined Growth Investors has sole power to vote 2,244,845 shares and sole power to dispose of 2,380,514 shares, with no shared voting or dispositive power reported. The filing lists Disciplined Growth Investors’ principal business office in Minneapolis, Minnesota.

Key Figures

Beneficially owned shares: 2,380,514 shares Percent of class: 10.0% Sole voting power: 2,244,845 shares +3 more

6 metrics

Beneficially owned shares 2,380,514 shares Proto Labs common stock beneficially owned by Disciplined Growth Investors

Percent of class 10.0% Portion of Proto Labs common stock outstanding held by Disciplined Growth Investors

Sole voting power 2,244,845 shares Shares for which Disciplined Growth Investors has sole power to vote or direct the vote

Shared voting power 0 shares Shares for which Disciplined Growth Investors has shared voting power

Sole dispositive power 2,380,514 shares Shares for which Disciplined Growth Investors has sole power to dispose or direct disposition

Shared dispositive power 0 shares Shares for which Disciplined Growth Investors has shared dispositive power

Key Terms

beneficially owned, sole power to vote, sole power to dispose, Schedule 13G/A

4 terms

beneficially owned financial

"Amount beneficially owned: 2,380,514"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

sole power to vote financial

"Sole power to vote or to direct the vote: 2,244,845"

sole power to dispose financial

"Sole power to dispose or to direct the disposition of: 2,380,514"

Schedule 13G/A regulatory

"Form type: SCHEDULE 13G/A institutional ownership filing"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

FAQ

What percentage of Proto Labs Inc (PRLB) does Disciplined Growth Investors own?

Disciplined Growth Investors beneficially owns 10.0% of Proto Labs Inc common stock, totaling 2,380,514 shares as of June 30, 2026, according to the Schedule 13G/A ownership disclosure.

How many Proto Labs (PRLB) shares does Disciplined Growth Investors report?

Disciplined Growth Investors reports beneficial ownership of 2,380,514 Proto Labs common shares. This stake represents 10.0% of the outstanding common stock, with all dispositive power held on a sole basis.

What voting power does Disciplined Growth Investors have in Proto Labs (PRLB)?

Disciplined Growth Investors has sole voting power over 2,244,845 shares of Proto Labs common stock and no shared voting power, as disclosed in the Schedule 13G/A filing.

Does Disciplined Growth Investors share dispositive power over Proto Labs (PRLB) shares?

No. The filing states Disciplined Growth Investors has sole power to dispose of 2,380,514 shares of Proto Labs common stock and shared dispositive power over 0 shares.

Who signed the Schedule 13G/A for Proto Labs (PRLB) on behalf of Disciplined Growth Investors?

The Schedule 13G/A is signed by Peter G. Rieke, identified as Chief Operating & Compliance Officer of Disciplined Growth Investors, dated August 14, 2026.

AI-generated analysis. How Rhea-AI works. Not financial advice.

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Available on EDGAR 08/14/2026 - 03:56 PM Accepted by SEC EDGAR 08/14/2026 - 03:55 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 9)

Proto Labs Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

743713109

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 743713109

1

Names of Reporting Persons

DISCIPLINED GROWTH INVESTORS INC /MN

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

MINNESOTA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 2,244,845.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,380,514.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,380,514.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

10.0 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Proto Labs Inc
(b)	Address of issuer's principal executive offices: 5540 Pioneer Creek, 5540 Pioneer Creek, Maple Plain, MINNESOTA, 55359.
Item 2.
(a)	Name of person filing: Disciplined Growth Investors, Inc.
(b)	Address or principal business office or, if none, residence: 150 South Fifth Street Suite 2550 Minneapolis, MN 55402
(c)	Citizenship: Minnesota, USA
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 743713109
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 2,380,514
(b)	Percent of class: 10.0 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 2,244,845
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 2,380,514
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

DISCIPLINED GROWTH INVESTORS INC /MN

Signature:	Peter G. Rieke
Name/Title:	Chief Operating & Compliance Officer
Date:	08/14/2026