Mesa Laboratories Inc
Ownership
Ownership Structure
Who owns Mesa Laboratories Inc (MLAB)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 88.4% of the shares are freely tradable; institutional investors hold 93.8%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Long Path Partners, LP | 8.53 | 477,126 | +17.6 | 06/30/2026 |
| BlackRock Inc | 7.04 | 393,851 | -1.2 | 03/31/2026 |
| Boston Partners Global Investors, Inc | 4.74 | 265,149 | -1.3 | 06/30/2026 |
| Vanguard Capital Management, LLC | 4.16 | 232,643 | +0.0 | 03/31/2026 |
| Ranger Investment Management LP | 3.11 | 173,988 | -14.3 | 06/30/2026 |
| AQR Capital Management LLC | 3.05 | 170,562 | +143.2 | 03/31/2026 |
| Morgan Stanley - Brokerage Accounts | 2.90 | 162,116 | -7.7 | 03/31/2026 |
| Royce & Associates, LP | 2.88 | 161,229 | +5.1 | 03/31/2026 |
| Diamond Hill Capital Management, LLC | 2.78 | 155,771 | +0.3 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Vanguard MStar Total Stk Mkt Idx Invest | 3.01 | 168,511 | +0.0 | 07/31/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Sullivan John James | Director | 20,618 | 2,620,548 $ | Aug 15, 2026 | direct |
| Ladiwala Shiraz Shabanali | Director | 12,333 | 1,567,524 $ | Aug 15, 2026 | direct |
| Tripeny R Tony | Director | 9,082 | 1,154,322 $ | Aug 15, 2026 | direct |
| Alltoft Jennifer Sadie | Director | 7,662 | 973,840 $ | Aug 15, 2026 | direct |
| Kadia Siddhartha | President and CEO | 7,093 | 901,520 $ | Aug 13, 2026 | indirect |
| Hall Shannon | Director | 6,973 | 886,268 $ | Aug 15, 2026 | direct |
| Capone Mark Christopher | Director | 6,213 | 789,672 $ | Aug 15, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Aug 15, 2026 | Capone Mark Christopher | Director | Other | 2,784 | 0.00 | – |
| Aug 15, 2026 | Alltoft Jennifer Sadie | Director | Other | 2,784 | 0.00 | – |
| Aug 15, 2026 | Ladiwala Shiraz Shabanali | Director | Other | 3,810 | 0.00 | – |
| Aug 15, 2026 | Hall Shannon | Director | Other | 2,784 | 0.00 | – |
| Aug 15, 2026 | Tripeny R Tony | Director | Other | 2,784 | 0.00 | – |
| Aug 15, 2026 | Sullivan John James | Director | Other | 2,784 | 0.00 | – |
| Aug 13, 2026 | Sullivan John James | Director | Sell | 7,093 | 112.80 | 800,090 |
| Aug 13, 2026 | Kadia Siddhartha | President and CEO | Buy | 7,093 | 112.80 | 800,090 |
| Aug 13, 2026 | Tripeny R Tony | Director | Buy | 900 | 113.69 | 102,321 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: September 17, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.