eFFECTOR Therapeutics, Inc.
eFFECTOR Therapeutics, Inc. (EFTR) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · EFTR · as of Sep 30, 2025
Ownership Breakdown
1
Institutional Holders
▲ 1 vs Q2
$0
Total Inst. Value
4.70M
Shares Outstanding
freeFloat 99.19%
100
13F Shares Held
▲ 100 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
EFTR largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 1 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
BARCLAYS PLC pharmaceutical preparations | 100 | 0.37% | 0.37% | $4,000 | Mar 19, 2026 | 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
0
Increased
+0 shares1
New Positions
first time holders0
Decreased
−0 shares0
Sold Out
fully exitedNet shares change (top 50)
+0
+0 / −0
Net new holders
+1
1 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
EFTR insider trading · insider activity
Source: SEC Form 4
Insiders have been primarily selling shares recently. Selling may be driven by pre-scheduled Rule 10b5-1 plans rather than negative sentiment.
8
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 |
|---|---|---|---|---|---|---|---|
Loewy Caroline M director | Jun 13, 2024 | Award | 800 | $1.38 | $1.1K | 800 | Form 4 ↗ |
Klencke Barbara director | Jun 13, 2024 | Award | 800 | $1.38 | $1.1K | 800 | Form 4 ↗ |
Ehrlich Christopher B director | Jun 13, 2024 | Award | 800 | $1.38 | $1.1K | 800 | Form 4 ↗ |
Harrington-Smith Kristen director | Jun 13, 2024 | Award | 800 | $1.38 | $1.1K | 800 | Form 4 ↗ |
Gallagher Brian M. Jr. director | Jun 13, 2024 | Award | 800 | $1.38 | $1.1K | 800 | Form 4 ↗ |
Bhatt Elizabeth director | Jun 13, 2024 | Award | 800 | $1.38 | $1.1K | 800 | Form 4 ↗ |
Byrnes Michael Chief Financial Officer | May 15, 2024 | Award | 1,387 | $1.68 | $2.3K | 3.1K | Form 4 ↗ |
WORLAND STEPHEN T Chief Executive Officer | May 15, 2024 | Award | 1,806 | $1.68 | $3.0K | 12.5K | Form 4 ↗ |
Loewy Caroline M director | Feb 19, 2024 | Award | 2,000 | $11.32 | $22.6K | 2.0K | Form 4 ↗ |
Bhatt Elizabeth director | Feb 19, 2024 | Award | 2,000 | $11.32 | $22.6K | 2.0K | 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
eFFECTOR Therapeutics, Inc. (EFTR) is primarily owned by institutional investors, who hold approximately 0.0% of total shares outstanding. Company insiders own approximately 0.81%, while retail and public investors account for the remaining 99.19%.
The largest institutional shareholder of eFFECTOR Therapeutics, Inc. is BARCLAYS PLC, holding approximately 100 shares — equal to 0.37% of outstanding shares — as of September 30, 2025.
A total of 1 institutional investors currently hold EFTR stock, with a combined institutional value of approximately $0 as of the most recent 13F filing period.
Frequently asked questions
EFTR ownershipeFFECTOR Therapeutics, Inc. (EFTR) is primarily owned by institutional investors, who hold approximately 0.0% of shares. The largest shareholder is BARCLAYS PLC with a 0.37% stake. Company insiders hold 0.81%. Data sourced from SEC Form 13F as of September 30, 2025.