Long Path funds and affiliated managers amend a Schedule 13G to report ownership of 405,583 shares of Mesa Laboratories, Inc. Common Stock, equal to 7.3% of the class. Percentage is based on 5,524,813 shares outstanding as of January 31, 2026. The shares are directly held by Long Path Smaller Companies Fund, LP; the Reporting Persons disclaim beneficial ownership except to the extent of their pecuniary interest. This filing is Amendment No. 1 to the previously filed Schedule 13G.
Positive
None.
Negative
None.
Insights
Long Path reports a meaningful passive stake (7.3%) in Mesa Laboratories.
The filing shows the Fund holds 405,583 shares, with voting and dispositive power reported as shared among listed entities and individuals. The 7.3% figure uses the issuer's disclosed outstanding share count as of January 31, 2026.
Because this is a Schedule 13G amendment, it indicates passive investment reporting rather than an activist intent; subsequent filings would show any change in intent or ownership size.
Key Figures
Reported shares held:405,583 sharesPercent of class:7.3%Form type:Schedule 13G/A (Amendment No. 1)+1 more
4 metrics
Reported shares held405,583 sharesDirectly held by Long Path Smaller Companies Fund, LP
Percent of class7.3%Calculated using 5,524,813 shares outstanding as of 01/31/2026
Form typeSchedule 13G/A (Amendment No. 1)Amendment to prior 13G filed March 13, 2026
Shares outstanding (context)5,524,813 sharesIssuer's Form 10-Q for period ended 12/31/2025 (as of 01/31/2026)
Key Terms
Schedule 13G/A, beneficial ownership, shared dispositive power
3 terms
Schedule 13G/Aregulatory
"This Amendment No. 1 to the Schedule 13G is filed by"
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.
beneficial ownershipfinancial
"Each Reporting Person disclaims beneficial ownership of such shares"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
shared dispositive powerfinancial
"Shared Dispositive Power 405,583.00"
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 1)
Mesa Laboratories, Inc.
(Name of Issuer)
Common Stock, no par value
(Title of Class of Securities)
59064R109
(CUSIP Number)
03/31/2026
(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):
59064R109
1
Names of Reporting Persons
Long Path Smaller Companies Fund, LP
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
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
405,583.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
405,583.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
405,583.00
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)
7.3 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP Number(s):
59064R109
1
Names of Reporting Persons
Long Path Fund GP, LLC
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
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
405,583.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
405,583.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
405,583.00
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)
7.3 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP Number(s):
59064R109
1
Names of Reporting Persons
Long Path Partners, LP
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
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
405,583.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
405,583.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
405,583.00
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)
7.3 %
12
Type of Reporting Person (See Instructions)
IA, PN
SCHEDULE 13G
CUSIP Number(s):
59064R109
1
Names of Reporting Persons
Long Path Holdings LLC
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
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
405,583.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
405,583.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
405,583.00
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)
7.3 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP Number(s):
59064R109
1
Names of Reporting Persons
William Thomas Brennan
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
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
405,583.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
405,583.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
405,583.00
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)
7.3 %
12
Type of Reporting Person (See Instructions)
IN, HC
SCHEDULE 13G
CUSIP Number(s):
59064R109
1
Names of Reporting Persons
Brian Paul Nelson
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
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
405,583.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
405,583.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
405,583.00
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)
7.3 %
12
Type of Reporting Person (See Instructions)
IN, HC
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Mesa Laboratories, Inc.
(b)
Address of issuer's principal executive offices:
12100 West Sixth Ave., Lakewood, CO 80228
Item 2.
(a)
Name of person filing:
This Amendment No. 1 to Schedule 13G is filed by (i) Long Path Smaller Companies Fund, LP (the "Fund"), (ii) Long Path Fund GP, LLC (the "Fund GP"), as the general partner of the Fund, (iii) Long Path Partners, LP (the "Adviser"), as the investment adviser to the Fund, (iv) Long Path Holdings LLC (the "Adviser GP"), as the general partner of the Adviser, (v) William Thomas Brennan, as the managing member of the Fund GP and the Adviser GP and co-portfolio manager of the Fund, and (vi) Brian Paul Nelson, as co-portfolio manager of the Fund and a member of the Adviser GP (each, a "Reporting Person" and collectively, the "Reporting Persons"). Reference is hereby made to the Schedule 13G filed with the Securities and Exchange Commission by the Reporting Persons with respect to the Common Stock of the Issuer on March 13, 2026 (the "Schedule 13G"). The agreement among the Reporting Persons to file jointly (the "Joint Filing Agreement") was filed as Exhibit A to the initial filing of the Schedule 13G. The shares reported herein are directly held by the Fund and each Reporting Person disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.
(b)
Address or principal business office or, if none, residence:
c/o Long Path Partners, 1 Landmark Square, Suite 1920, Stamford, CT 06901
(c)
Citizenship:
The Fund is a Delaware limited partnership. The Fund GP is a Delaware limited liability company. The Adviser is a Delaware limited partnership. The Adviser GP is a Delaware limited liability company. William Thomas Brennan and Brian Paul Nelson are citizens of the United States.
(d)
Title of class of securities:
Common Stock, no par value
(e)
CUSIP No.:
59064R109
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:
The information required by this paragraph is set forth in the cover pages to this Schedule 13G/A and is incorporated herein by reference.
(b)
Percent of class:
The information required by this paragraph is set forth in the cover pages to this Schedule 13G/A and is incorporated herein by reference. Percentage ownership is based on 5,524,813 shares of Common Stock outstanding as of January 31, 2026, as reported in the Issuer's Report on Form 10-Q for the period ended December 31, 2025 filed with the Securities and Exchange Commission on February 3, 2026.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
The information required by this paragraph is set forth in the cover pages to this Schedule 13G/A and is incorporated herein by reference.
(ii) Shared power to vote or to direct the vote:
The information required by this paragraph is set forth in the cover pages to this Schedule 13G/A and is incorporated herein by reference.
(iii) Sole power to dispose or to direct the disposition of:
The information required by this paragraph is set forth in the cover pages to this Schedule 13G/A and is incorporated herein by reference.
(iv) Shared power to dispose or to direct the disposition of:
The information required by this paragraph is set forth in the cover pages to this Schedule 13G/A and is incorporated herein by reference.
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 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.
Long Path Smaller Companies Fund, LP
Signature:
/s/ William Thomas Brennan
Name/Title:
William Thomas Brennan/Managing Member of Long Path Fund GP, LLC, its general partner
Date:
04/15/2026
Long Path Fund GP, LLC
Signature:
/s/ William Thomas Brennan
Name/Title:
William Thomas Brennan/Managing Member
Date:
04/15/2026
Long Path Partners, LP
Signature:
/s/ William Thomas Brennan
Name/Title:
William Thomas Brennan/Managing Member of Long Path Holdings LLC, its general partner
What stake does Long Path report in Mesa Laboratories (MLAB)?
Long Path reports ownership of 405,583 shares, representing 7.3% of common stock. This percentage uses a base of 5,524,813 shares outstanding as of January 31, 2026 per the issuer's 10-Q.
Who exactly filed the Schedule 13G/A for Mesa Laboratories (MLAB)?
The amendment is filed jointly by Long Path Smaller Companies Fund, LP; Long Path Fund GP, LLC; Long Path Partners, LP; Long Path Holdings LLC; William T. Brennan; and Brian P. Nelson, as Reporting Persons.
Are the reported shares directly held or beneficially owned by the managers?
The shares are directly held by Long Path Smaller Companies Fund, LP. The Reporting Persons disclaim beneficial ownership except to the extent of their pecuniary interest in the Fund.
What date is used to calculate the percentage ownership in the filing?
Percentage ownership is calculated using 5,524,813 shares outstanding as of January 31, 2026, as reported in the issuer's Form 10-Q for the period ended December 31, 2025.
