Larimar Therapeutics, Inc.
Larimar Therapeutics, Inc. (LRMR) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · LRMR · as of Sep 30, 2025
Ownership Breakdown
155
Institutional Holders
▲ 29 vs Q2
$276.25M
Total Inst. Value
▲ $96.12M vs Q2
85.58M
Shares Outstanding
freeFloat 59.78%
85.53M
13F Shares Held
▲ 23.20M vs Q2
Institutional ownership = 13F shares ÷ total outstanding. Insider % = 100 − free float. Public % = free float − institution %. Data: FMP /symbol-positions-summary + /shares-float + SEC EDGAR.
Top Institutional Holders
LRMR largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C) pharmaceutical preparations | 30.61M | 47.80% | 47.80% | $98.86B | Nov 14, 2025 | ▲ 9.38M |
RA CAPITAL MANAGEMENT, L.P. pharmaceutical preparations | 6.05M | 9.44% | 9.44% | $19.53B | Nov 14, 2025 | — held |
BLUE OWL CAPITAL HOLDINGS LP pharmaceutical preparations | 5.85M | 9.14% | 9.14% | $18.91B | Nov 12, 2025 | ▲ 925.0K |
MILLENNIUM MANAGEMENT LLC pharmaceutical preparations | 4.90M | 7.65% | 7.65% | $15.82B | Nov 14, 2025 | ▲ 1.24M |
OPALEYE MANAGEMENT INC. pharmaceutical preparations | 3.72M | 5.81% | 5.81% | $10.56B | Nov 14, 2025 | ▼ 389.1K |
BLACKROCK, INC. pharmaceutical preparations | 3.34M | 5.22% | 5.22% | $10.79B | Nov 12, 2025 | ▲ 299.2K |
RTW INVESTMENTS, LP pharmaceutical preparations | 3.13M | 4.88% | 4.88% | $10.09B | Nov 14, 2025 | NEW |
VANGUARD GROUP INC pharmaceutical preparations | 3.09M | 4.82% | 4.82% | $9.97B | Nov 7, 2025 | ▲ 945.8K |
LOGOS GLOBAL MANAGEMENT LP pharmaceutical preparations | 2.50M | 3.90% | 3.90% | $8.07B | Nov 14, 2025 | — held |
ADAGE CAPITAL PARTNERS GP, L.L.C. pharmaceutical preparations | 1.90M | 2.97% | 2.97% | $6.14B | Nov 14, 2025 | NEW |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q3 2025 vs prior quarter
Q3 2025
27
Increased
+18.98M shares14
New Positions
first time holders5
Decreased
−1.80M shares0
Sold Out
fully exitedNet shares change (top 50)
+17.18M
+18.98M / −1.80M
Net new holders
+36
14 new / 0 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
LRMR insider trading · insider activity
Source: SEC Form 4
Insiders have been net buyers of shares recently. Selling may be driven by pre-scheduled Rule 10b5-1 plans rather than negative sentiment.
6
Buy transactions
0
Sell transactions
0.00
Buy/Sell ratio
$0M
Total disposed
Recent Insider Transactions
Showing 10 most recent · Common Stock only
| Name · Role | Date | Type | Shares | Price | Value | After Trans. | Filing |
|---|---|---|---|---|---|---|---|
Flynn James E * Director by Deputization | May 19, 2026 | Award | 55,150 | $3.33 | $183.6K | 55.1K | Form 4 ↗ |
LEFF JONATHAN S director | May 19, 2026 | Award | 55,150 | $3.33 | $183.6K | 55.1K | Form 4 ↗ |
SHERMAN JEFFREY W director | May 19, 2026 | Award | 55,150 | $3.33 | $183.6K | 55.1K | Form 4 ↗ |
Truitt Joseph director | May 19, 2026 | Award | 55,150 | $3.33 | $183.6K | 55.1K | Form 4 ↗ |
THOMAS FRANK E director | May 19, 2026 | Award | 55,150 | $3.33 | $183.6K | 55.1K | Form 4 ↗ |
Hamilton Thomas Edward director | May 19, 2026 | Award | 55,150 | $3.33 | $183.6K | 55.1K | Form 4 ↗ |
Flynn James E * Director by Deputization | Feb 27, 2026 | Purchase | 1,084,012 | $5.00 | $5.42M | 10.62M | Form 4 ↗ |
Flynn James E * Director by Deputization | Feb 27, 2026 | Purchase | 1,084,010 | $5.00 | $5.42M | 10.62M | Form 4 ↗ |
Flynn James E * Director by Deputization | Feb 27, 2026 | Purchase | 831,978 | $5.00 | $4.16M | 8.15M | Form 4 ↗ |
Flynn James E * Director by Deputization | Feb 27, 2026 | Purchase | 2,000,000 | $5.00 | $10.00M | 6.21M | Form 4 ↗ |
Source: /insider-trading/search (FMP stable). Buy/Sell direction: acquisitionOrDisposition A=Buy, D=Sell. RSU vesting (M-Exempt) excluded from sentiment bar. All data from SEC EDGAR public filings.
About institutional & insider ownership
Larimar Therapeutics, Inc. (LRMR) is primarily owned by institutional investors, who hold approximately 99.9% of total shares outstanding. Company insiders own approximately 40.22%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Larimar Therapeutics, Inc. is DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C), holding approximately 30.61 million shares — equal to 47.80% of outstanding shares — as of September 30, 2025.
A total of 155 institutional investors currently hold LRMR stock, with a combined institutional value of approximately $276,246,532 as of the most recent 13F filing period.
Frequently asked questions
LRMR ownershipLarimar Therapeutics, Inc. (LRMR) is primarily owned by institutional investors, who hold approximately 99.9% of shares. The largest shareholder is DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C) with a 47.80% stake. Company insiders hold 40.22%. Data sourced from SEC Form 13F as of September 30, 2025.