Tectonic Therapeutic, Inc.
TECX- Exchange
- Nasdaq
- Industry
- Biological Products, (No Diagnostic Substances)
- SEC CIK
- 0001681087
In the last 90 days, Tectonic Therapeutic, Inc. insiders filed 0 open-market purchases and 3 sales; 122 institutions reported holding it in 13F filings for Q2 2026, worth $479.9M in total; no superinvestor holds it.
Holders of 5% or more of TECX
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Tectonic Therapeutic, Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| Springer Timothy A | 13D/A | 31.50%4.31M shares | +2.30 ppfrom 29.20% | Feb 10, 20252 filings | Apr 7, 2025 | SEC |
| FMR LLC | 13G/A | 15.00%2.80M shares | +4.70 ppfrom 10.30% | Jan 8, 20252 filings | May 12, 2025 | SEC |
| ADAR1 Partners, LP | 13G | 7.40%3.28M shares | New | Feb 23, 20241 filing | Feb 23, 2024 | SEC |
| McGuire Terrance | 13D/A | 6.30%658.0K shares | 0.00 ppfrom 6.30% | Feb 7, 20252 filings | Apr 7, 2025 | SEC |
| TCG Crossover GP II, LLC | 13G | 6.20%1.17M shares | New | Feb 27, 20261 filing | Feb 27, 2026 | SEC |
| Standard Life Aberdeen plc | 13G | 6.10%1.14M shares | New | Jan 29, 20261 filing | Jan 29, 2026 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
16 Schedule 13D and 13G filings on Tectonic Therapeutic, Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Feb 27, 20265:17 PM ET | TCG Crossover GP II, LLCand 4 others | 13G | 6.20%1.17M shares | New | Feb 12, 2026 | SEC |
| Jan 29, 20263:15 PM ET | Standard Life Aberdeen plcand 1 other | 13G | 6.10%1.14M shares | New | Dec 31, 2025 | SEC |
| Nov 14, 20254:17 PM ET | EcoR1 Capital, LLCand 2 others | 13G/A | 0.00%0 shares | −5.00 ppfrom 5.00%Below 5% | Sep 30, 2025 | SEC |
| Nov 14, 20258:24 AM ET | Deep Track Capital, LPand 2 others | 13G/A | 0.00%0 shares | −7.60 ppfrom 7.60%Below 5% | Sep 30, 2025 | SEC |
| May 15, 20252:24 PM ET | EcoR1 Capital, LLCand 2 others | 13G/A | 5.00%935.1K shares | – | Mar 31, 2025 | SEC |
| May 12, 202510:43 AM ET | FMR LLCand 1 other | 13G/A | 15.00%2.80M shares | +4.70 ppfrom 10.30% | Mar 31, 2025 | SEC |
| Apr 7, 20257:20 PM ET | Springer Timothy Aand 2 others | 13D/A | 31.50%4.31M shares | +2.30 ppfrom 29.20% | Apr 3, 2025 | SEC |
| Apr 7, 20255:19 PM ET | McGuire Terranceand 7 others | 13D/A | 6.30%658.0K shares | 0.00 ppfrom 6.30% | Apr 3, 2025 | SEC |
| Apr 7, 20254:20 PM ET | Vida Ventures II, LLCand 2 others | 13D/A | 0.00%0 shares | −5.60 ppfrom 5.60%Below 5% | Mar 4, 2025 | SEC |
| Feb 13, 20253:10 PM ET | BML Investment Partners, L.P. | 13G/A | 0.00%0 shares | –Below 5% | Dec 31, 2024 | SEC |
| Feb 10, 20254:04 PM ET | Deep Track Capital, LPand 2 others | 13G | 7.60%1.40M shares | New | Feb 3, 2025 | SEC |
| Feb 10, 20256:19 AM ET | Springer Timothy Aand 2 others | 13D/A | 29.20%4.23M shares | – | Feb 5, 2025 | SEC |
| Feb 7, 20255:51 PM ET | Vida Ventures II, LLCand 2 others | 13D/A | 5.60%1.03M shares | – | Feb 5, 2025 | SEC |
| Feb 7, 20254:51 PM ET | McGuire Terranceand 7 others | 13D/A | 6.30%1.16M shares | – | Feb 5, 2025 | SEC |
| Jan 8, 20259:40 AM ET | FMR LLCand 1 other | 13G/A | 10.30%1.52M shares | – | Dec 31, 2024 | SEC |
| Feb 23, 20244:00 PM ET | ADAR1 Partners, LPand 3 others | 13G | 7.40%3.28M shares | New | Feb 15, 2024 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Tectonic Therapeutic, Inc. shares.
No Form 144 notices for Tectonic Therapeutic, Inc. are on file.