Tectonic Therapeutic, Inc. (TECX) shareholders
TECXNasdaqBiological Products, (No Diagnostic Substances)Fiscal year ends December 31
$21.04−0.92 (-4.19%)
Close on Nov 12, 2026Market cap $411.32MP/E –Yield 0.00%
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
71.4%
14M of 20M shares
Institutional holders
123
25 new, 11 sold out
Net institutional buying
0M
In Q2 2026
Insider trades, 12 months
3 buys · 11 sales
Net sold $415.85K
Shares held by institutions
Holders of more than 5%
Latest Schedule 13D (active) or 13G (passive) filed by each holder
| Holder | Shares | % of class | Filing | As of |
|---|---|---|---|---|
| Timothy A. Springer Joint filing with TAS Partners LLC (7.40%) | 4,313,558 | 31.50% | 13D (active) amendment | Apr 3, 2025 |
| ADAR1 Capital Management GP, LLC Joint filing with ADAR1 Partners, LP (7.40%), ADAR1 Capital Management, LLC (7.40%) and 1 more | 3,276,498 | 7.40% | 13G (passive) | Feb 15, 2024 |
| FMR LLC Joint filing with Abigail P. Johnson (15.00%) | 2,799,400 | 15.00% | 13G (passive) amendment | Mar 31, 2025 |
| Abigail P. Johnson Joint filing with FMR LLC (10.30%) | 1,516,335 | 10.30% | 13G (passive) amendment | Dec 31, 2024 |
| Deep Track Capital, LP Joint filing with Deep Track Biotechnology Master Fund, Ltd. (7.60%), David Kroin (7.60%) | 1,401,938 | 7.60% | 13G (passive) | Feb 3, 2025 |
| Chen Yu | 1,169,760 | 6.20% | 13G (passive) | Feb 12, 2026 |
| VV Manager II, LLC Joint filing with Vida Ventures II, LLC (5.40%) | 1,028,674 | 5.60% | 13D (active) amendment | Feb 5, 2025 |
| Terrance McGuire | 657,976 | 6.30% | 13D (active) amendment | Apr 3, 2025 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of TECX | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| FMR LLC | 2,830,378 | 14.48% | $97.29M | +13,884 | 0.00% |
| TCG Crossover Management, LLC | 1,204,891 | 6.16% | $41.42M | – | 1.00% |
| abrdn plc | 1,141,824 | 5.84% | $39.25M | – | 0.06% |
| BlackRock, Inc. | 862,592 | 4.41% | $29.65M | +2,240 | 0.00% |
| First Light Asset Management, LLC | 800,726 | 4.10% | $27.52M | +152,983 | 1.67% |
| Baker Bros. Advisors LP | 607,788 | 3.11% | $20.89M | – | 0.10% |
| 5AM Venture Management, LLC | 606,660 | 3.10% | $20.85M | – | 7.24% |
| Braidwell LP | 596,900 | 3.05% | $20.52M | −250,251 | 0.76% |
| Vanguard Capital Management LLC | 488,805 | 2.50% | $16.80M | +15,273 | 0.00% |
| Vestal Point Capital, LP | 425,000 | 2.17% | $14.61M | +97,000 | 0.34% |
| Bollard Group LLC | 302,953 | 1.55% | $10.41M | – | 0.32% |
| Kennedy Capital Management LLC | 282,202 | 1.44% | $9.70M | −4,480 | 0.17% |
| Geode Capital Management, LLC | 270,461 | 1.38% | $9.30M | +2,188 | 0.00% |
| Orbimed Advisors LLC | 226,600 | 1.16% | $7.79M | – | 0.14% |
| State Street Corp | 219,908 | 1.12% | $7.56M | +6,403 | 0.00% |
| Ikarian Capital, LLC | 205,837 | 1.05% | $7.08M | +48,300 | 0.76% |
| D. E. Shaw & Co., Inc. | 186,550 | 0.95% | $6.41M | +70,430 | 0.00% |
| Marshall Wace, Llp | 172,101 | 0.88% | $5.92M | −57,494 | 0.00% |
| Millennium Management LLC | 165,525 | 0.85% | $5.69M | +107,177 | 0.00% |
| Squarepoint Ops LLC | 145,028 | 0.74% | $4.99M | −19,391 | 0.01% |
Institutional buying and selling by quarter
Positions opened, added to, reduced and closed by 13F filers
| Quarter | Holders | Shares held | % of shares | New / added | Reduced / closed | Shares bought | Shares sold |
|---|---|---|---|---|---|---|---|
| Q2 2026 | 123 | 14M | 71.4% | 25 / 39 | 40 / 11 | 1M | 1M |
| Q1 2026 | 111 | 14M | 70.6% | 29 / 33 | 37 / 20 | 4M | 3M |
| Q4 2025 | 105 | 14M | 70.7% | 30 / 35 | 24 / 23 | 4M | 3M |
| Q3 2025 | 99 | 12M | 62.0% | 28 / 30 | 20 / 11 | 3M | 3M |
| Q2 2025 | 82 | 12M | 62.0% | 18 / 34 | 13 / 14 | 2M | 1M |
| Q1 2025 | 78 | 11M | 57.4% | 30 / 29 | 12 / 22 | 6M | 2M |
| Q4 2024 | 70 | 8M | 39.3% | 25 / 21 | 15 / 8 | 2M | 1M |
| Q3 2024 | 53 | 7M | 36.9% | 19 / 12 | 9 / 4 | 3M | 1M |
| Q2 2024 | 39 | 5M | 27.3% | 39 / 0 | 0 / 0 | 5M | 0M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
122 funds held TECX in Q2 2026, 31% of their shares through ETFs. Each fund counts once per quarter, from its quarter-end report.
| Fund | Shares | % of TECX | Value | % of fund | As of |
|---|---|---|---|---|---|
| Fidelity Growth Company Fund | 720,235 | 3.68% | $22.45M | 0.02% | May 31, 2026 |
| Select Biotechnology Portfolio | 405,389 | 2.07% | $12.63M | 0.24% | May 31, 2026 |
| Vanguard Total Stock Market Index Fund | 364,413 | 1.86% | $12.53M | 0.00% | Jun 30, 2026 |
| iShares Russell 2000 ETF | 268,951 | 1.38% | $9.25M | 0.01% | Jun 30, 2026 |
| Fidelity Growth Company K6 Fund | 248,743 | 1.27% | $7.75M | 0.03% | May 31, 2026 |
| Fidelity Series Growth Company Fund | 196,522 | 1.01% | $6.12M | 0.03% | May 31, 2026 |
| Columbia Small Cap Growth Fund | 121,484 | 0.62% | $3.79M | 0.10% | May 31, 2026 |
| Fidelity Advisor Biotechnology Fund | 120,995 | 0.62% | $3.39M | 0.15% | Jul 31, 2026 |
| Fidelity Small Cap Index Fund | 112,159 | 0.57% | $3.14M | 0.01% | Jul 31, 2026 |
| Vanguard Extended Market Index Fund | 111,919 | 0.57% | $3.85M | 0.00% | Jun 30, 2026 |
| iShares Russell 2000 Value ETF | 78,065 | 0.40% | $2.68M | 0.02% | Jun 30, 2026 |
| iShares Biotechnology ETF | 66,553 | 0.34% | $2.29M | 0.03% | Jun 30, 2026 |
| Vanguard Russell 2000 Index Fund | 56,310 | 0.29% | $1.75M | 0.01% | May 31, 2026 |
| Fidelity Extended Market Index Fund | 50,753 | 0.26% | $1.58M | 0.00% | May 31, 2026 |
| iShares Micro-Cap ETF | 34,417 | 0.18% | $1.18M | 0.08% | Jun 30, 2026 |
Officers, directors and major owners
People who filed Forms 3, 4 or 5 in the last two years
| Name | Role | Shares owned | % of shares | Latest filing |
|---|---|---|---|---|
| Alise Reicin | Chief Executive Officer, Director | 446,108 | 2.28% | Oct 28, 2026 |
| Daniel Lochner | Chief Financial Officer | 58,024 | 0.30% | Oct 2, 2026 |
| Peter McNamara | Chief Scientific Officer | 54,305 | 0.28% | Oct 2, 2026 |
| Marc Schwabish | Chief Business Officer | 44,903 | 0.23% | Oct 2, 2026 |
| Marcella K. Ruddy | Chief Medical Officer | 67,157 | 0.34% | Oct 2, 2026 |
| Jessica Caroline Chutter | Director | – | – | Jun 10, 2026 |
| Phillip B. Donenberg | Director | 2,000 | 0.01% | Jun 10, 2026 |
| Timothy A. Springer | Director, 10% owner | 6,024,338 | 30.82% | Jun 10, 2026 |
| Stefan Vitorovic | Director | 1,000,900 | 5.12% | Jun 10, 2026 |
| Praveen P. Tipirneni | Director | 3,037 | 0.02% | Jun 10, 2026 |
| Francois Nader | Director | – | – | Apr 3, 2026 |
| Terrance McGuire | Director | 573,062 | 2.93% | Jun 11, 2025 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Alise Reicin Chief Executive Officer, Director | Oct 26, 2026 | Option exercise | +10,000 | $2.38 | $23.80K | 319,078 |
| Peter McNamara Chief Scientific Officer | Sep 30, 2026 | Sale(10b5-1 plan) | −536 | $23.04 | $12.35K | 54,305 |
| Marcella K. Ruddy Chief Medical Officer | Sep 25, 2026 | Tax withholding | −525 | $23.67 | $12.43K | 67,157 |
| Peter McNamara Chief Scientific Officer | Sep 25, 2026 | Tax withholding | −444 | $23.67 | $10.51K | 54,841 |
| Marc Schwabish Chief Business Officer | Sep 25, 2026 | Tax withholding | −411 | $23.67 | $9.73K | 44,903 |
| Daniel Lochner Chief Financial Officer | Sep 25, 2026 | Tax withholding | −520 | $23.67 | $12.31K | 58,024 |
| Alise Reicin Chief Executive Officer, Director | Sep 25, 2026 | Tax withholding | −1,545 | $23.67 | $36.57K | 309,078 |
| Peter McNamara Chief Scientific Officer | Aug 25, 2026 | Option exercise | +43 | $14.71 | $633 | 55,328 |
| Peter McNamara Chief Scientific Officer | Aug 25, 2026 | Sale(10b5-1 plan) | −43 | $36.52 | $1.57K | 55,285 |
| Peter McNamara Chief Scientific Officer | Aug 12, 2026 | Sale(10b5-1 plan) | −43 | $35.00 | $1.51K | 55,285 |
| Peter McNamara Chief Scientific Officer | Aug 12, 2026 | Option exercise | +43 | $14.71 | $633 | 55,328 |
| Peter McNamara Chief Scientific Officer | Jun 30, 2026 | Sale(10b5-1 plan) | −172 | $35.00 | $6.02K | 55,285 |
| Peter McNamara Chief Scientific Officer | Jun 30, 2026 | Option exercise | +172 | $14.71 | $2.53K | 55,457 |
| Alise Reicin Chief Executive Officer, Director | Jun 20, 2026 | Tax withholding | −924 | $30.34 | $28.03K | 310,623 |
| Marcella K. Ruddy Chief Medical Officer | May 4, 2026 | Sale(10b5-1 plan) | −1,065 | $30.00 | $31.95K | 67,682 |
| Marcella K. Ruddy Chief Medical Officer | Apr 1, 2026 | Sale(10b5-1 plan) | −1,000 | $31.05 | $31.05K | 68,747 |
| Marcella K. Ruddy Chief Medical Officer | Mar 6, 2026 | Sale(10b5-1 plan) | −10,000 | $30.00 | $300.00K | 69,747 |
| Peter McNamara Chief Scientific Officer | Mar 6, 2026 | Option exercise | +2,500 | $2.38 | $5.95K | 61,332 |
| Peter McNamara Chief Scientific Officer | Mar 6, 2026 | Sale(10b5-1 plan) | −6,047 | $30.00 | $181.41K | 55,500 |
| Peter McNamara Chief Scientific Officer | Mar 6, 2026 | Option exercise | +215 | $14.71 | $3.16K | 61,547 |
| Peter McNamara Chief Scientific Officer | Mar 6, 2026 | Sale(10b5-1 plan) | −215 | $35.00 | $7.53K | 55,285 |
| Alise Reicin Chief Executive Officer, Director | Mar 4, 2026 | Award | +76,500 | – | – | 311,547 |
| Marc Schwabish Chief Business Officer | Mar 4, 2026 | Award | +19,500 | – | – | 45,314 |
| Daniel Lochner Chief Financial Officer | Mar 4, 2026 | Award | +26,500 | – | – | 58,544 |
| Peter McNamara Chief Scientific Officer | Mar 4, 2026 | Award | +23,000 | – | – | 60,482 |
| Peter McNamara Chief Scientific Officer | Mar 4, 2026 | Sale(10b5-1 plan) | −1,650 | $25.00 | $41.25K | 58,832 |
| Marcella K. Ruddy Chief Medical Officer | Mar 4, 2026 | Award | +26,500 | – | – | 79,747 |
| Peter McNamara Chief Scientific Officer | Mar 3, 2026 | Sale(10b5-1 plan) | −1,649 | $22.06 | $36.38K | 37,482 |
| Alise Reicin Chief Executive Officer, Director | Feb 11, 2026 | Buy | +2,500 | $21.10 | $52.75K | 127,030 |
| Alise Reicin Chief Executive Officer, Director | Feb 11, 2026 | Buy | +2,500 | $21.10 | $52.75K | 237,547 |
| Marc Schwabish Chief Business Officer | Feb 10, 2026 | Option exercise | +4,500 | $2.38 | $10.71K | 25,814 |
| Daniel Lochner Chief Financial Officer | Feb 10, 2026 | Buy | +6,000 | $21.61 | $129.66K | 32,044 |
| Peter McNamara Chief Scientific Officer | Feb 4, 2026 | Tax withholding | −1,748 | $23.22 | $40.59K | 39,131 |
| Marc Schwabish Chief Business Officer | Feb 4, 2026 | Tax withholding | −1,619 | $23.22 | $37.59K | 21,314 |
| Daniel Lochner Chief Financial Officer | Feb 4, 2026 | Tax withholding | −2,077 | $23.22 | $48.23K | 26,044 |
| Marcella K. Ruddy Chief Medical Officer | Feb 4, 2026 | Tax withholding | −2,064 | $23.22 | $47.93K | 53,247 |
| Alise Reicin Chief Executive Officer, Director | Feb 4, 2026 | Tax withholding | −4,104 | $23.22 | $95.29K | 235,047 |
| Alise Reicin Chief Executive Officer, Director | Dec 31, 2025 | Option exercise | +10,966 | $2.38 | $26.10K | 239,151 |
| Peter McNamara Chief Scientific Officer | Dec 22, 2025 | Option exercise | +7,000 | $2.98 | $20.86K | 40,879 |
| Peter McNamara Chief Scientific Officer | Sep 25, 2025 | Award | +4,550 | – | – | 33,879 |
| Marc Schwabish Chief Business Officer | Sep 25, 2025 | Award | +4,210 | – | – | 22,933 |
| Daniel Lochner Chief Financial Officer | Sep 25, 2025 | Award | +5,430 | – | – | 28,121 |
| Marcella K. Ruddy Chief Medical Officer | Sep 25, 2025 | Award | +5,370 | – | – | 55,311 |
| Alise Reicin Chief Executive Officer, Director | Sep 25, 2025 | Award | +14,700 | – | – | 228,185 |
| Alise Reicin Chief Executive Officer, Director | Jun 20, 2025 | Tax withholding | −859 | $19.81 | $17.02K | 213,485 |
| Timothy A. Springer Director, 10% owner | Apr 11, 2025 | Buy | +9,478 | $16.31 | $154.59K | 4,334,846 |
| Timothy A. Springer Director, 10% owner | Apr 11, 2025 | Buy | +53,706 | $16.31 | $875.94K | 1,503,358 |
| Timothy A. Springer Director, 10% owner | Apr 10, 2025 | Buy | +45,858 | $16.73 | $767.20K | 1,449,652 |
| Timothy A. Springer Director, 10% owner | Apr 10, 2025 | Buy | +8,092 | $16.73 | $135.38K | 4,325,368 |
| Timothy A. Springer Director, 10% owner | Apr 9, 2025 | Buy | +16,215 | $14.62 | $237.06K | 1,398,938 |
| Timothy A. Springer Director, 10% owner | Apr 9, 2025 | Buy | +4,856 | $15.23 | $73.96K | 1,403,794 |
| Timothy A. Springer Director, 10% owner | Apr 9, 2025 | Buy | +857 | $15.23 | $13.05K | 4,317,276 |
| Timothy A. Springer Director, 10% owner | Apr 9, 2025 | Buy | +2,861 | $14.62 | $41.83K | 4,316,419 |
| Timothy A. Springer Director, 10% owner | Apr 7, 2025 | Buy | +87,500 | $17.10 | $1.50M | 4,313,558 |
| Timothy A. Springer Director, 10% owner | Apr 7, 2025 | Buy | +412,500 | $17.10 | $7.05M | 1,382,723 |
| Terrance McGuire Director | Apr 7, 2025 | Sale | −500,000 | $17.10 | $8.55M | 573,062 |
| Timothy A. Springer Director, 10% owner | Feb 5, 2025 | Buy | +660,000 | $50.00 | $33.00M | 970,223 |
| Timothy A. Springer Director, 10% owner | Feb 5, 2025 | Buy | +129,294 | $54.14 | $7.00M | 4,226,058 |
| Daniel Lochner Chief Financial Officer | Feb 5, 2025 | Buy | +4,617 | $54.14 | $249.96K | 4,617 |
| Daniel Lochner Chief Financial Officer | Feb 4, 2025 | Award | +18,074 | – | – | 18,074 |
Awards, option exercises, tax withholding and gifts are shown alongside open-market buys and sales. Each name links to the filing on SEC EDGAR.
Short interest
Shares sold short and not yet bought back, as of Oct 30, 2026 (FINRA, reported twice a month)
Short % of float
21.23%
2M shares short
Days to cover
13.7
At 0M shares a day
Change since last report
+6.8%
From 2M shares
Short volume, 20 days
57.6%
Of volume reported to FINRA
Shares sold short, last 12 months
Short sale volume counts trades marked short on any given day, including market-maker hedging, so it runs far higher than the share of Tectonic Therapeutic's stock actually held short. Settlement fails (shares not delivered on time) peaked at 19,728 shares on Aug 24, 2026 over the last 90 days.
Planned insider sales
Notices of proposed sale filed on Form 144 before shares are sold
| Seller | Filed | Shares | Market value | Planned sale | Acquired through |
|---|---|---|---|---|---|
| Peter McNamara Officer | Sep 30, 2026 | 493 | $11.51K | Sep 30, 2026 | Restricted Stock Units |
| Terrance McGuire Former Director | Aug 27, 2026 | 7,513 | $276.72K | Aug 27, 2026 | Stock Option Exercise |
| Terrance McGuire Former Director | Aug 21, 2026 | 10,200 | $383.67K | Aug 21, 2026 | Stock Option Exercise |
| Peter McNamara Officer | Aug 12, 2026 | 129 | $4.11K | Aug 12, 2026 | Exercise of Stock Options |
| Peter McNamara Officer | Jun 30, 2026 | 172 | $5.69K | Jun 30, 2026 | Exercise of Stock Options |
| Marcella K. Ruddy Officer | Mar 6, 2026 | 12,065 | $336.01K | Mar 6, 2026 | Restricted Stock Units |
| Peter McNamara Officer | Mar 6, 2026 | 6,262 | $174.40K | Mar 6, 2026 | Exercise of Stock Options |
| Peter McNamara Officer | Mar 4, 2026 | 1,650 | $40.25K | Mar 4, 2026 | Restricted Stock Units |
| Peter McNamara Officer | Mar 3, 2026 | 1,649 | $37.93K | Mar 3, 2026 | Restricted Stock Units |
| Petersen Deanna M Officer | Jul 14, 2023 | 128,648 | $177.53K | Jul 14, 2023 | STOCK OPTION EXERCISE |
| Geoff MacKay Former CEO | Jun 7, 2023 | 146,927 | $173.37K | Jun 7, 2023 | Option Exercise |
| Geoff MacKay Former CEO | Jun 5, 2023 | 7,152 | $7.94K | Jun 5, 2023 | Option Exercise |
| Geoff MacKay Former CEO | May 25, 2023 | 186,841 | $227.95K | May 25, 2023 | Private Transaction/Founders Shares |
| The Mac C. MacKay Irrevocable Trust Child of former CEO | May 24, 2023 | 72,604 | $57.34M | May 24, 2023 | Private Transaction/Founders Shares |
| The Kali M MacKay Irrevocable Trust DTD 1/6/2022 Child of Former CEO | May 24, 2023 | 72,604 | $57.34M | May 24, 2023 | Private Transaction/Founders Shares |
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