Cabaletta Bio, Inc. (CABA) shareholders
CABANasdaqBiological Products, (No Diagnostic Substances)Fiscal year ends December 31
$1.28−0.05 (-3.76%)
Close on Nov 13, 2026Market cap $217.02MP/E –Yield –
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
93.6%
159M of 170M shares
Institutional holders
140
55 new, 23 sold out
Net institutional buying
74M
In Q2 2026
Insider trades, 12 months
8 buys · 0 sales
Net bought $296.21K
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 |
|---|---|---|---|---|
| Prudential Financial Inc | 24,267,980 | 11.40% | 13G (passive) amendment | May 31, 2026 |
| Jennison Associates LLC | 24,267,980 | 11.40% | 13G (passive) amendment | May 29, 2026 |
| T. Rowe Price Investment Management, Inc. | 17,250,098 | 8.00% | 13G (passive) amendment | Sep 30, 2026 |
| Bain Capital Life Sciences Opportunities III, LP | 17,241,445 | 9.99% | 13G (passive) amendment | Jun 30, 2026 |
| Phillip Gross Joint filing with Adage Capital Management, L.P. (8.43%), Robert Atchinson (8.43%) | 14,174,758 | 8.43% | 13G (passive) amendment | Jun 30, 2026 |
| BlackRock, Inc. | 13,013,495 | 7.70% | 13G (passive) amendment | Sep 30, 2026 |
| Bihua Chen Joint filing with Cormorant Asset Management, LP (9.03%) | 10,500,000 | 9.03% | 13G (passive) amendment | Mar 31, 2026 |
| Cormorant Asset Management, LP Joint filing with Bihua Chen (5.95%) | 10,000,000 | 5.95% | 13G (passive) amendment | Jun 30, 2026 |
| Adage Capital Management, L.P. Joint filing with Robert Atchinson (9.99%), Phillip Gross (9.99%) | 9,002,580 | 9.99% | 13G (passive) amendment | Jun 30, 2025 |
| Norges Bank | 8,775,653 | 5.38% | 13G (passive) | Jun 30, 2026 |
| Anand Parekh Joint filing with Alyeska Investment Group, L.P. (6.03%), Alyeska Fund GP, LLC (6.03%) | 5,800,000 | 6.03% | 13G (passive) amendment | Sep 30, 2025 |
| Israel A. Englander Joint filing with Millennium Management LLC (5.30%), Millennium Group Management LLC (5.30%) | 5,130,763 | 5.30% | 13G (passive) | Feb 11, 2026 |
| Robert Atchinson Joint filing with Adage Capital Partners, L.P. (9.47%), Adage Capital Partners GP, L.L.C. (9.47%) and 2 more | 3,864,475 | 9.47% | 13G (passive) amendment | Dec 31, 2023 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of CABA | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| Jennison Associates LLC | 20,033,730 | 11.82% | $62.30M | +11,063,152 | 0.04% |
| T. Rowe Price Investment Management, Inc. | 18,869,907 | 11.13% | $58.69M | +7,789,902 | 0.04% |
| Bain Capital Life Sciences Investors, LLC | 17,241,445 | 10.17% | $53.62M | +7,564,320 | 3.19% |
| BlackRock, Inc. | 10,754,701 | 6.34% | $33.45M | +8,381,698 | 0.00% |
| Adage Capital Partners Gp, L.L.C. | 9,174,758 | 5.41% | $28.53M | +345,000 | 0.04% |
| State Street Corp | 7,839,305 | 4.62% | $24.38M | +7,369,327 | 0.00% |
| Vanguard Capital Management LLC | 7,227,018 | 4.26% | $22.48M | +3,198,027 | 0.00% |
| Cormorant Asset Management, LP | 5,000,000 | 2.95% | $15.55M | −500,000 | 0.80% |
| Price T Rowe Associates Inc /Md/ | 4,418,674 | 2.61% | $13.74M | +3,976,397 | 0.00% |
| Woodline Partners LP | 4,200,142 | 2.48% | $13.06M | +2,949,900 | 0.04% |
| Norges Bank | 4,112,401 | 2.43% | $12.79M | New | 0.00% |
| Opaleye Management Inc. | 3,863,800 | 2.28% | $12.02M | +2,483,800 | 1.09% |
| Citadel Advisors LLC | 3,522,112 | 2.08% | $10.95M | New | 0.00% |
| Geode Capital Management, LLC | 3,459,464 | 2.04% | $10.76M | +2,326,219 | 0.00% |
| Franklin Resources Inc | 2,413,937 | 1.42% | $7.51M | New | 0.00% |
| Goldman Sachs Group Inc | 2,211,825 | 1.30% | $6.88M | +1,428,605 | 0.00% |
| Millennium Management LLC | 2,068,491 | 1.22% | $6.43M | −3,834,790 | 0.00% |
| Cantor Fitzgerald, L. P. | 1,600,002 | 0.94% | $4.98M | +835,002 | 0.03% |
| Marshall Wace, Llp | 1,565,939 | 0.92% | $4.87M | −613,879 | 0.00% |
| Renaissance Technologies LLC | 1,535,300 | 0.91% | $4.77M | −501,363 | 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 | 140 | 159M | 93.6% | 55 / 50 | 20 / 23 | 84M | 10M |
| Q1 2026 | 108 | 85M | 49.9% | 27 / 31 | 28 / 13 | 18M | 9M |
| Q4 2025 | 95 | 80M | 47.3% | 30 / 33 | 19 / 8 | 19M | 9M |
| Q3 2025 | 75 | 70M | 41.4% | 10 / 24 | 31 / 21 | 13M | 16M |
| Q2 2025 | 86 | 73M | 42.9% | 26 / 23 | 28 / 32 | 46M | 10M |
| Q1 2025 | 92 | 36M | 21.4% | 16 / 29 | 32 / 30 | 6M | 8M |
| Q4 2024 | 108 | 38M | 22.7% | 25 / 40 | 25 / 37 | 7M | 17M |
| Q3 2024 | 120 | 48M | 28.5% | 20 / 45 | 36 / 41 | 13M | 12M |
| Q2 2024 | 142 | 52M | 30.7% | 19 / 54 | 49 / 35 | 14M | 15M |
| Q1 2024 | 159 | 53M | 31.3% | 46 / 47 | 46 / 15 | 14M | 10M |
| Q4 2023 | 128 | 49M | 28.9% | 42 / 41 | 31 / 10 | 16M | 8M |
| Q3 2023 | 97 | 41M | 24.1% | 26 / 47 | 10 / 12 | 7M | 3M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
114 funds held CABA in Q2 2026, 41% of their shares through ETFs. Each fund counts once per quarter, from its quarter-end report.
| Fund | Shares | % of CABA | Value | % of fund | As of |
|---|---|---|---|---|---|
| T. Rowe Price Small-Cap Value Fund, Inc. | 7,865,614 | 4.64% | $24.46M | 0.23% | Jun 30, 2026 |
| State Street(R) SPDR(R) S&P(R) Biotech ETF | 5,256,225 | 3.10% | $16.35M | 0.15% | Jun 30, 2026 |
| Vanguard Total Stock Market Index Fund | 5,215,188 | 3.08% | $16.22M | 0.00% | Jun 30, 2026 |
| PGIM Jennison Health Sciences Fund | 4,960,717 | 2.93% | $18.75M | 1.35% | May 29, 2026 |
| iShares Russell 2000 ETF | 2,926,762 | 1.73% | $9.10M | 0.01% | Jun 30, 2026 |
| PGIM Jennison Small Company Fund | 2,696,273 | 1.59% | $8.39M | 0.24% | Jun 30, 2026 |
| Vanguard Extended Market Index Fund | 1,878,039 | 1.11% | $5.84M | 0.01% | Jun 30, 2026 |
| T. Rowe Price Health Sciences Fund, Inc. | 1,795,663 | 1.06% | $5.58M | 0.05% | Jun 30, 2026 |
| T. Rowe Price Small-Cap Stock Fund, Inc. | 1,387,457 | 0.82% | $4.31M | 0.05% | Jun 30, 2026 |
| T. Rowe Price New Horizons Fund, Inc. | 1,369,957 | 0.81% | $4.26M | 0.03% | Jun 30, 2026 |
| Fidelity Small Cap Index Fund | 1,229,372 | 0.73% | $3.29M | 0.01% | Jul 31, 2026 |
| iShares Biotechnology ETF | 1,007,313 | 0.59% | $3.13M | 0.03% | Jun 30, 2026 |
| Franklin Biotechnology Discovery Fund | 876,846 | 0.52% | $2.35M | 0.20% | Jul 31, 2026 |
| T. Rowe Price Institutional Small-Cap Stock Fund | 746,576 | 0.44% | $2.32M | 0.05% | Jun 30, 2026 |
| Fidelity Extended Market Index Fund | 662,486 | 0.39% | $2.50M | 0.01% | May 31, 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 |
|---|---|---|---|---|
| Steven Nichtberger | President & CEO, Director | 1,394,483 | 0.82% | Mar 2, 2026 |
| David J. Chang | Chief Medical Officer | 8,800 | 0.01% | Mar 2, 2026 |
| Arun Das | Chief Business Officer | – | – | Mar 2, 2026 |
| Michael Gerard | General Counsel | 6,600 | 0.00% | Mar 2, 2026 |
| Anup Marda | Chief Financial Officer | 50,000 | 0.03% | Mar 2, 2026 |
| Gwendolyn Binder | President, Science & Tech. | 31,312 | 0.02% | Mar 2, 2026 |
| Steve Gavel | Chief Commercial Officer | 22,170 | 0.01% | Jan 21, 2026 |
| Catherine Bollard | Director | 5,405 | 0.00% | Jun 10, 2026 |
| Scott C. Brun | Director | – | – | Jun 10, 2026 |
| Mark Simon | Director | 154,205 | 0.09% | Jun 10, 2026 |
| Shawn Tomasello | Director | 22,725 | 0.01% | Jun 10, 2026 |
| Richard C. Henriques Jr | Director | – | – | Jun 10, 2026 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Gwendolyn Binder President, Science & Tech. | Jan 21, 2026 | Buy | +11,312 | $2.19 | $24.77K | 31,312 |
| Steve Gavel Chief Commercial Officer | Jan 21, 2026 | Buy | +22,170 | $2.27 | $50.33K | 22,170 |
| Steven Nichtberger President & CEO, Director | Jan 21, 2026 | Buy | +45,000 | $2.24 | $100.80K | 1,031,483 |
| Mark Simon Director | Jan 21, 2026 | Buy | +11,061 | $2.28 | $25.22K | 147,205 |
| Shawn Tomasello Director | Jan 21, 2026 | Buy | +22,725 | $2.21 | $50.22K | 22,725 |
| Michael Gerard General Counsel | Jan 21, 2026 | Buy | +6,600 | $2.27 | $14.98K | 6,600 |
| Catherine Bollard Director | Jan 21, 2026 | Buy | +4,405 | $2.27 | $10.00K | 5,405 |
| David J. Chang Chief Medical Officer | Jan 21, 2026 | Buy | +8,800 | $2.26 | $19.89K | 8,800 |
| Gwendolyn Binder See Remarks | Jan 19, 2024 | Sale(10b5-1 plan) | −700 | $20.33 | $14.23K | 20,000 |
| Gwendolyn Binder See Remarks | Jan 19, 2024 | Sale(10b5-1 plan) | −10,300 | $19.54 | $201.26K | 20,700 |
| Gwendolyn Binder See Remarks | Jan 19, 2024 | Option exercise | +11,000 | $1.01 | $11.11K | 31,000 |
| Gwendolyn Binder See Remarks | Dec 19, 2023 | Option exercise | +11,000 | $1.01 | $11.11K | 31,000 |
| Gwendolyn Binder See Remarks | Dec 19, 2023 | Sale(10b5-1 plan) | −7,868 | $21.76 | $171.21K | 23,132 |
| Gwendolyn Binder See Remarks | Dec 19, 2023 | Sale(10b5-1 plan) | −3,132 | $22.22 | $69.59K | 20,000 |
| Gwendolyn Binder See Remarks | Nov 20, 2023 | Sale(10b5-1 plan) | −7,458 | $18.02 | $134.39K | 20,000 |
| Gwendolyn Binder See Remarks | Nov 20, 2023 | Option exercise | +11,000 | $1.01 | $11.11K | 31,000 |
| Gwendolyn Binder See Remarks | Nov 20, 2023 | Sale(10b5-1 plan) | −3,542 | $17.39 | $61.60K | 27,458 |
| Gwendolyn Binder See Remarks | Oct 19, 2023 | Sale(10b5-1 plan) | −408 | $14.28 | $5.83K | 20,000 |
| Gwendolyn Binder See Remarks | Oct 19, 2023 | Sale(10b5-1 plan) | −10,592 | $13.32 | $141.09K | 20,408 |
| Gwendolyn Binder See Remarks | Oct 19, 2023 | Option exercise | +11,000 | $1.01 | $11.11K | 31,000 |
| Gwendolyn Binder See Remarks | Sep 19, 2023 | Sale(10b5-1 plan) | −10,300 | $17.50 | $180.25K | 20,700 |
| Gwendolyn Binder See Remarks | Sep 19, 2023 | Option exercise | +11,000 | $1.01 | $11.11K | 31,000 |
| Gwendolyn Binder See Remarks | Sep 19, 2023 | Sale(10b5-1 plan) | −700 | $18.50 | $12.95K | 20,000 |
| Gwendolyn Binder See Remarks | Aug 21, 2023 | Sale(10b5-1 plan) | −300 | $13.82 | $4.15K | 20,000 |
| Gwendolyn Binder See Remarks | Aug 21, 2023 | Option exercise | +11,000 | $1.01 | $11.11K | 31,000 |
| Gwendolyn Binder See Remarks | Aug 21, 2023 | Sale(10b5-1 plan) | −10,700 | $13.41 | $143.49K | 20,300 |
| Gwendolyn Binder See Remarks | Jul 19, 2023 | Option exercise | +11,000 | $1.01 | $11.11K | 31,000 |
| Gwendolyn Binder See Remarks | Jul 19, 2023 | Sale(10b5-1 plan) | −8,185 | $13.67 | $111.89K | 22,815 |
| Gwendolyn Binder See Remarks | Jul 19, 2023 | Sale(10b5-1 plan) | −2,815 | $14.26 | $40.14K | 20,000 |
| Gwendolyn Binder See Remarks | Jun 20, 2023 | Sale(10b5-1 plan) | −11,000 | $12.99 | $142.89K | 20,000 |
| Gwendolyn Binder See Remarks | Jun 20, 2023 | Option exercise | +11,000 | $1.01 | $11.11K | 31,000 |
| Gwendolyn Binder See Remarks | May 19, 2023 | Sale(10b5-1 plan) | −22,000 | $11.81 | $259.82K | 20,000 |
| Gwendolyn Binder See Remarks | May 19, 2023 | Option exercise | +22,000 | $1.01 | $22.22K | 42,000 |
| Steven Nichtberger President & CEO, Director | Oct 19, 2022 | Buy | +8,127 | $1.25 | $10.16K | 986,483 |
| Anup Marda Chief Financial Officer | Oct 18, 2022 | Buy | +50,000 | $0.99 | $49.50K | 50,000 |
| Steven Nichtberger President & CEO, Director | Oct 18, 2022 | Buy | +141,873 | $0.99 | $140.45K | 978,356 |
| Mark Simon Director | Oct 18, 2022 | Buy | +7,000 | $0.98 | $6.86K | 7,000 |
| Mark Simon Director | Oct 18, 2022 | Buy | +118,000 | $0.98 | $115.64K | 136,144 |
| Catherine Bollard Director | Oct 18, 2022 | Buy | +1,000 | $0.99 | $990 | 1,000 |
| Gwendolyn Binder See Remarks | Oct 18, 2022 | Buy | +20,000 | $0.99 | $19.80K | 20,000 |
| Steven Nichtberger President & CEO, Director | Jan 31, 2022 | Option exercise | +50,000 | $1.01 | $50.50K | 836,483 |
| 5AM Partners V, LLC 10% owner | Nov 1, 2021 | Sale | −36,544 | $13.00 | $475.07K | 333,144 |
| 5AM Partners V, LLC 10% owner | Nov 1, 2021 | Sale | −258,456 | $13.00 | $3.36M | 1,731,119 |
| 5AM Ventures V, L.P. 10% owner | Sep 7, 2021 | Sale | −625,000 | $9.70 | $6.06M | 1,989,575 |
| Scott M. Rocklage 10% owner | Jan 12, 2021 | Sale | −74,470 | $13.00 | $968.11K | 2,614,575 |
| Scott M. Rocklage 10% owner | Jan 12, 2021 | Sale | −10,530 | $13.00 | $136.89K | 369,688 |
| Scott M. Rocklage 10% owner | Jan 8, 2021 | Sale | −37,411 | $13.00 | $486.34K | 380,218 |
| Scott M. Rocklage 10% owner | Jan 8, 2021 | Sale | −264,589 | $13.00 | $3.44M | 2,689,045 |
| Andrew J. Schwab 10% owner | Dec 10, 2020 | Sale | −36,916 | $14.75 | $544.51K | 417,629 |
| Andrew J. Schwab 10% owner | Dec 10, 2020 | Sale | −261,084 | $14.75 | $3.85M | 2,953,634 |
| Andrew J. Schwab 10% owner | Oct 29, 2019 | Buy | +454,545 | $11.00 | $5.00M | 454,545 |
| Andrew J. Schwab 10% owner | Oct 29, 2019 | Conversion | +3,214,721 | – | – | 3,214,721 |
| Deerfield Management Company, L.P. 10% owner | Oct 29, 2019 | Buy | +700,000 | $11.00 | $7.70M | 700,000 |
| Deerfield Management Company, L.P. 10% owner | Oct 29, 2019 | Conversion | +464,253 | – | – | 464,253 |
| Deerfield Management Company, L.P. 10% owner | Oct 29, 2019 | Conversion | +464,253 | – | – | 464,253 |
| Steven Nichtberger President & CEO, Director | Oct 29, 2019 | Conversion | +60,483 | – | – | 786,483 |
| Mark Simon Director | Oct 29, 2019 | Conversion | +18,144 | – | – | 18,144 |
| Jeremy Green 10% owner | Oct 29, 2019 | Conversion | +696,378 | – | – | 696,378 |
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
23.09%
38M shares short
Days to cover
8.2
At 5M shares a day
Change since last report
-2.3%
From 39M shares
Short volume, 20 days
50.3%
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 Cabaletta Bio's stock actually held short. Settlement fails (shares not delivered on time) peaked at 63,795 shares on Aug 28, 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 |
|---|---|---|---|---|---|
| Gwendolyn Binder Officer | Nov 20, 2023 | 33,000 | $592.68K | Nov 20, 2023 | Exercise of Stock Options |
| Gwendolyn Binder Officer | Oct 19, 2023 | 11,000 | $148.01K | Oct 19, 2023 | Exercise of Stock Options |
| Gwendolyn Binder Officer | Sep 19, 2023 | 11,000 | $205.15K | Sep 19, 2023 | Exercise of Stock Options |
| Gwendolyn Binder Officer | Aug 21, 2023 | 11,000 | $139.48K | Aug 21, 2023 | Exercise of Stock Options |
| Gwendolyn Binder Officer | Jul 19, 2023 | 11,000 | $153.78K | Jul 19, 2023 | Exercise of Stock Options |
| Gwendolyn Binder Officer | Jun 20, 2023 | 11,000 | $144.32K | Jun 20, 2023 | Exercise of Stock Options |
| Gwendolyn Binder Officer | Jun 20, 2023 | 11,000 | $144.32K | Jun 20, 2023 | Exercise of Stock Options |
| Gwendolyn Binder Officer | May 19, 2023 | 22,000 | $270.60K | May 19, 2023 | Exercise of Stock Options |
See a number that looks wrong?