SIONNasdaqPharmaceutical PreparationsFiscal year ends December 31
Sionna Therapeutics, Inc.
Financials through Q2 FY2026, quarter ended Jun 30, 2026Last filing: 10-Q on Aug 6, 2026
$4.01+0.12 (+3.08%)
Close on Oct 19, 2026
- Market cap
- $181.05M
- P/E (TTM)
- –
- Dividend yield
- –
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
100.0%
48M of 45M shares
Institutional holders
147
35 new, 8 sold out
Net institutional buying
3M
In Q2 2026
Insider trades, 12 months
0 buys · 86 sales
Net sold $153.57M
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 |
|---|---|---|---|---|
| James G. Coulter | 6,684,962 | 15.20% | 13D (active) | Feb 10, 2025 |
| Peter Kolchinsky | 6,476,193 | 14.30% | 13D (active) amendment | Sep 17, 2026 |
| Shabet Rose Sharon | 3,195,181 | 7.10% | 13G (passive) amendment | Mar 31, 2026 |
| OrbiMed Capital GP VIII LLC | 2,967,722 | 6.60% | 13D (active) amendment | Apr 15, 2026 |
| Viking Global Investors LP | 2,952,754 | 6.70% | 13G (passive) | Feb 10, 2025 |
| Atlas Venture Associates XI, LLC | 2,886,293 | 6.50% | 13D (active) | Feb 10, 2025 |
| Sionna Aggregator, LP | 2,478,030 | 5.60% | 13D (active) | Feb 10, 2025 |
| Atlas Venture Fund XI, L.P. | 2,382,495 | 5.40% | 13D (active) amendment | Oct 16, 2025 |
| RA Capital Management, L.P. | 10,071,712 | 22.60% | 13D (active) amendment | Nov 5, 2025 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of SION | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| Ra Capital Management, L.P. | 9,905,045 | 21.91% | $435.72M | – | 3.79% |
| Tpg Gp A, LLC | 6,494,962 | 14.37% | $285.71M | – | 5.71% |
| Viking Global Investors LP | 3,195,181 | 7.07% | $140.56M | – | 0.40% |
| Atlas Venture Life Science Advisors, LLC | 2,995,602 | 6.63% | $131.78M | – | 14.95% |
| Orbimed Advisors LLC | 2,555,877 | 5.65% | $112.43M | −974,825 | 2.08% |
| Enavate Sciences Gp, LLC | 2,478,030 | 5.48% | $109.01M | – | 31.56% |
| Adage Capital Partners Gp, L.L.C. | 1,600,000 | 3.54% | $70.38M | +1,450,000 | 0.10% |
| JPMorgan Chase & Co | 1,490,508 | 3.30% | $64.09M | +25,494 | 0.00% |
| BlackRock, Inc. | 1,474,769 | 3.26% | $64.88M | +178,902 | 0.00% |
| Jennison Associates LLC | 1,172,133 | 2.59% | $51.56M | −279,087 | 0.03% |
| Citadel Advisors LLC | 1,147,636 | 2.54% | $50.48M | −19,295 | 0.01% |
| Vanguard Capital Management LLC | 1,132,001 | 2.50% | $49.80M | +102,504 | 0.00% |
| State Street Corp | 1,021,534 | 2.26% | $44.94M | +265,307 | 0.00% |
| Perceptive Advisors LLC | 905,000 | 2.00% | $39.81M | +246,561 | 0.60% |
| Deerfield Management Company, L.P. (Series C) | 680,916 | 1.51% | $29.95M | −289,674 | 0.31% |
| Siren, L.L.C. | 610,515 | 1.35% | $26.86M | +310,515 | 0.54% |
| Price T Rowe Associates Inc /Md/ | 478,016 | 1.06% | $21.03K | −278,360 | 0.00% |
| Eventide Asset Management, LLC | 474,981 | 1.05% | $20.89M | −170,549 | 0.28% |
| Geode Capital Management, LLC | 457,145 | 1.01% | $20.11M | +67,273 | 0.00% |
| Casdin Capital, LLC | 400,000 | 0.88% | $17.60M | New | 0.88% |
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 | 147 | 48M | 100.0% | 35 / 57 | 40 / 8 | 6M | 3M |
| Q1 2026 | 122 | 46M | 100.0% | 32 / 41 | 30 / 9 | 4M | 2M |
| Q4 2025 | 101 | 44M | 97.2% | 30 / 39 | 20 / 7 | 4M | 5M |
| Q3 2025 | 78 | 45M | 99.1% | 19 / 21 | 18 / 6 | 3M | 2M |
| Q2 2025 | 65 | 43M | 96.1% | 26 / 18 | 10 / 8 | 3M | 1M |
| Q1 2025 | 47 | 41M | 91.8% | 47 / 0 | 0 / 0 | 41M | 0M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
| Fund | Shares | % of SION | Value | % of fund | As of |
|---|---|---|---|---|---|
| Vanguard Total Stock Market Index Fund | 934,641 | 2.07% | $41.11M | 0.00% | Jun 30, 2026 |
| PGIM Jennison Health Sciences Fund | 651,048 | 1.44% | $27.88M | 2.01% | May 29, 2026 |
| State Street(R) SPDR(R) S&P(R) Biotech ETF | 647,694 | 1.43% | $28.49M | 0.27% | Jun 30, 2026 |
| JPMorgan Small Cap Growth Fund | 524,280 | 1.16% | $23.06M | 0.88% | Jun 30, 2026 |
| iShares Russell 2000 ETF | 483,961 | 1.07% | $21.29M | 0.03% | Jun 30, 2026 |
| Eventide Healthcare & Life Sciences Fund | 474,969 | 1.05% | $20.89M | 1.17% | Jun 30, 2026 |
| T. Rowe Price Health Sciences Fund, Inc. | 287,643 | 0.64% | $12.65M | 0.11% | Jun 30, 2026 |
| Fidelity Small Cap Index Fund | 201,838 | 0.45% | $9.51M | 0.03% | Jul 31, 2026 |
| iShares Biotechnology ETF | 185,693 | 0.41% | $8.17M | 0.09% | Jun 30, 2026 |
| iShares Russell 2000 Growth ETF | 173,168 | 0.38% | $7.62M | 0.05% | Jun 30, 2026 |
| Vanguard Extended Market Index Fund | 168,369 | 0.37% | $7.41M | 0.01% | Jun 30, 2026 |
| JPMorgan Small Cap Blend Fund | 166,643 | 0.37% | $7.33M | 0.43% | Jun 30, 2026 |
| Artisan International Small-Mid Fund | 116,442 | 0.26% | $5.12M | 0.20% | Jun 30, 2026 |
| Franklin Biotechnology Discovery Fund | 107,956 | 0.24% | $5.09M | 0.44% | Jul 31, 2026 |
| Vanguard Russell 2000 Index Fund | 83,317 | 0.18% | $3.57M | 0.02% | 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 |
|---|---|---|---|---|
| Michael Cloonan | President & CEO, Director | 765,393 | 1.69% | Sep 18, 2026 |
| Charlotte McKee | CMO and Head of R&D | 78,415 | 0.17% | Sep 18, 2026 |
| Elena Ridloff | CFO and CBO | 85,801 | 0.19% | Sep 18, 2026 |
| Jennifer Fitzpatrick | CLO and Head of Program Mgmt. | 28,133 | 0.06% | Sep 18, 2026 |
| Caroline Stark Beer | Chief Business Officer | – | – | Jan 6, 2026 |
| Ra Capital Management, L.P. | Director, 10% owner | 3,448,812 | 7.63% | Sep 21, 2026 |
| Capital Healthcare Fund LP RA | Director | – | – | Sep 21, 2026 |
| Rajeev M. Shah | Director, 10% owner | – | – | Sep 21, 2026 |
| RA Capital Nexus Fund III, L.P. | Director | 715,988 | 1.58% | Sep 21, 2026 |
| Peter Kolchinsky | Director, 10% owner | 2,198,082 | 4.86% | Sep 21, 2026 |
| RA Capital Nexus Fund, L.P. | Director | – | – | Sep 21, 2026 |
| Capital GP VIII LLC OrbiMed | Director | 2,469,959 | 5.46% | Jul 9, 2026 |
| Peter A. Thompson | Director | 2,469,959 | 5.46% | Jul 9, 2026 |
| Advisors Llc Orbimed | Director | 2,555,877 | 5.65% | Jul 9, 2026 |
| Harold Edward Fleming | Director | – | – | Jun 18, 2026 |
| Joanne L. Viney | Director | – | – | Jun 18, 2026 |
| Marcella K. Ruddy | Director | – | – | Jun 18, 2026 |
| Paul J. Clancy | Director | – | – | Jun 18, 2026 |
| Bruce Booth | Director | 3,057,453 | 6.76% | Jun 18, 2026 |
| Laurie Stelzer | Director | – | – | Jun 18, 2026 |
| Joshua Resnick | Director | – | – | Jun 18, 2026 |
| Lucian Iancovici | Director | – | – | Feb 6, 2025 |
| Jon Winkelried | 10% owner | 6,494,962 | 14.37% | Jan 26, 2026 |
| James G. Coulter | 10% owner | 6,744,962 | 14.92% | Jan 26, 2026 |
| Tpg Gp A, Llc | 10% owner | 6,684,962 | 14.79% | Jan 26, 2026 |
| Atlas Venture Fund XI, L.P. | 10% owner | 4,441,747 | 9.82% | Feb 10, 2025 |
| Atlas Venture Associates Opportunity II, LP | 10% owner | – | – | Feb 10, 2025 |
| Atlas Venture Opportunity Fund II, L.P. | 10% owner | – | – | Feb 10, 2025 |
| Atlas Venture Associates Opportunity II, LLC | 10% owner | – | – | Feb 10, 2025 |
| Atlas Venture Associates XI, LLC | 10% owner | – | – | Feb 10, 2025 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Ra Capital Management, L.P. Director, 10% owner | Sep 17, 2026 | Sale | −33,800 | $7.46 | $252.15K | 3,448,812 |
| Ra Capital Management, L.P. Director, 10% owner | Sep 17, 2026 | Sale | −3,415,011 | $6.32 | $21.58M | 3,482,612 |
| Charlotte McKee CMO and Head of R&D | Sep 17, 2026 | Award | +50,000 | – | – | 78,415 |
| Charlotte McKee CMO and Head of R&D | Sep 17, 2026 | Award | +50,000 | – | – | 128,415 |
| Jennifer Fitzpatrick CLO and Head of Program Mgmt. | Sep 17, 2026 | Award | +28,133 | – | – | 28,133 |
| Jennifer Fitzpatrick CLO and Head of Program Mgmt. | Sep 17, 2026 | Award | +28,132 | – | – | 56,265 |
| Elena Ridloff CFO and CBO | Sep 17, 2026 | Award | +47,269 | – | – | 85,801 |
| Elena Ridloff CFO and CBO | Sep 17, 2026 | Award | +47,268 | – | – | 133,069 |
| Michael Cloonan President & CEO, Director | Sep 17, 2026 | Award | +109,025 | – | – | 765,393 |
| Michael Cloonan President & CEO, Director | Sep 17, 2026 | Award | +109,025 | – | – | 656,368 |
| Peter A. Thompson Director | Jul 7, 2026 | Sale(10b5-1 plan) | −85,918 | $44.86 | $3.85M | 2,469,959 |
| Capital GP VIII LLC OrbiMed Director | Jul 7, 2026 | Sale(10b5-1 plan) | −85,918 | $44.86 | $3.85M | 2,469,959 |
| Jennifer Fitzpatrick Chief Legal Officer | Jul 6, 2026 | Sale(10b5-1 plan) | −10,250 | $43.60 | $446.90K | 0 |
| Jennifer Fitzpatrick Chief Legal Officer | Jul 6, 2026 | Option exercise | +10,250 | $6.11 | $62.63K | 10,250 |
| Peter A. Thompson Director | Jun 30, 2026 | Sale(10b5-1 plan) | −115,844 | $45.50 | $5.27M | 2,555,877 |
| Advisors Llc Orbimed Director | Jun 30, 2026 | Sale(10b5-1 plan) | −115,844 | $45.50 | $5.27M | 2,555,877 |
| Advisors Llc Orbimed Director | May 27, 2026 | Sale(10b5-1 plan) | −101 | $44.49 | $4.49K | 2,671,721 |
| Peter A. Thompson Director | May 27, 2026 | Sale(10b5-1 plan) | −101 | $44.49 | $4.49K | 2,671,721 |
| Advisors Llc Orbimed Director | May 11, 2026 | Sale(10b5-1 plan) | −184,639 | $46.22 | $8.53M | 2,671,822 |
| Peter A. Thompson Director | May 11, 2026 | Sale(10b5-1 plan) | −184,639 | $46.22 | $8.53M | 2,671,822 |
| Advisors Llc Orbimed Director | May 8, 2026 | Sale(10b5-1 plan) | −59,767 | $44.58 | $2.66M | 2,856,461 |
| Peter A. Thompson Director | May 8, 2026 | Sale(10b5-1 plan) | −59,767 | $44.58 | $2.66M | 2,856,461 |
| Advisors Llc Orbimed Director | May 7, 2026 | Sale(10b5-1 plan) | −48,546 | $44.61 | $2.17M | 2,916,228 |
| Peter A. Thompson Director | May 7, 2026 | Sale(10b5-1 plan) | −48,546 | $44.61 | $2.17M | 2,916,228 |
| Peter A. Thompson Director | Apr 18, 2026 | Sale(10b5-1 plan) | −2,948 | $44.52 | $131.24K | 2,964,774 |
| Advisors Llc Orbimed Director | Apr 18, 2026 | Sale(10b5-1 plan) | −2,948 | $44.52 | $131.24K | 2,964,774 |
| Peter A. Thompson Director | Apr 17, 2026 | Sale(10b5-1 plan) | −52,397 | $44.68 | $2.34M | 2,967,722 |
| Advisors Llc Orbimed Director | Apr 17, 2026 | Sale(10b5-1 plan) | −52,397 | $44.68 | $2.34M | 2,967,722 |
| Peter A. Thompson Director | Apr 16, 2026 | Sale(10b5-1 plan) | −226,906 | $45.34 | $10.29M | 3,020,119 |
| Advisors Llc Orbimed Director | Apr 16, 2026 | Sale(10b5-1 plan) | −226,906 | $45.34 | $10.29M | 3,020,119 |
| Peter A. Thompson Director | Apr 15, 2026 | Sale(10b5-1 plan) | −235,863 | $44.64 | $10.53M | 3,247,025 |
| Advisors Llc Orbimed Director | Apr 15, 2026 | Sale(10b5-1 plan) | −235,863 | $44.64 | $10.53M | 3,247,025 |
| Peter A. Thompson Director | Apr 14, 2026 | Sale(10b5-1 plan) | −47,814 | $44.51 | $2.13M | 3,482,888 |
| Advisors Llc Orbimed Director | Apr 14, 2026 | Sale(10b5-1 plan) | −47,814 | $44.51 | $2.13M | 3,482,888 |
| Jennifer Fitzpatrick Chief Legal Officer | Mar 5, 2026 | Option exercise | +10,250 | $6.11 | $62.63K | 10,250 |
| Jennifer Fitzpatrick Chief Legal Officer | Mar 5, 2026 | Sale(10b5-1 plan) | −10,250 | $33.86 | $347.07K | 0 |
| Capital GP VIII LLC OrbiMed Director | Feb 3, 2026 | Sale(10b5-1 plan) | −29,063 | $44.58 | $1.30M | 3,530,702 |
| Peter A. Thompson Director | Feb 3, 2026 | Sale(10b5-1 plan) | −29,063 | $44.58 | $1.30M | 3,530,702 |
| Capital GP VIII LLC OrbiMed Director | Feb 2, 2026 | Sale(10b5-1 plan) | −1,890 | $44.57 | $84.24K | 3,559,765 |
| Peter A. Thompson Director | Feb 2, 2026 | Sale(10b5-1 plan) | −1,890 | $44.57 | $84.24K | 3,559,765 |
| Jon Winkelried 10% owner | Jan 22, 2026 | Sale | −250,000 | $40.00 | $10.00M | 6,494,962 |
| Capital GP VIII LLC OrbiMed Director | Dec 24, 2025 | Sale(10b5-1 plan) | −33,356 | $44.55 | $1.49M | 3,561,655 |
| Peter A. Thompson Director | Dec 24, 2025 | Sale(10b5-1 plan) | −33,356 | $44.55 | $1.49M | 3,561,655 |
| Capital GP VIII LLC OrbiMed Director | Dec 19, 2025 | Sale(10b5-1 plan) | −875 | $44.49 | $38.93K | 3,595,011 |
| Peter A. Thompson Director | Dec 19, 2025 | Sale(10b5-1 plan) | −875 | $44.49 | $38.93K | 3,595,011 |
| Capital GP VIII LLC OrbiMed Director | Dec 18, 2025 | Sale(10b5-1 plan) | −100 | $44.49 | $4.45K | 3,595,886 |
| Peter A. Thompson Director | Dec 18, 2025 | Sale(10b5-1 plan) | −100 | $44.49 | $4.45K | 3,595,886 |
| Capital GP VIII LLC OrbiMed Director | Dec 17, 2025 | Sale(10b5-1 plan) | −900 | $44.50 | $40.05K | 3,595,986 |
| Peter A. Thompson Director | Dec 17, 2025 | Sale(10b5-1 plan) | −900 | $44.50 | $40.05K | 3,595,986 |
| Jennifer Fitzpatrick Chief Legal Officer | Dec 5, 2025 | Option exercise | +10,250 | $6.11 | $62.63K | 10,250 |
| Jennifer Fitzpatrick Chief Legal Officer | Dec 5, 2025 | Sale(10b5-1 plan) | −10,250 | $40.52 | $415.33K | 0 |
| Peter A. Thompson Director | Nov 26, 2025 | Sale(10b5-1 plan) | −1,600 | $44.49 | $71.18K | 3,596,886 |
| Advisors Llc Orbimed Director | Nov 26, 2025 | Sale(10b5-1 plan) | −1,600 | $44.49 | $71.18K | 3,596,886 |
| Peter A. Thompson Director | Nov 25, 2025 | Sale(10b5-1 plan) | −11,890 | $44.60 | $530.29K | 3,598,486 |
| Advisors Llc Orbimed Director | Nov 25, 2025 | Sale(10b5-1 plan) | −11,890 | $44.60 | $530.29K | 3,598,486 |
| Peter A. Thompson Director | Nov 24, 2025 | Sale(10b5-1 plan) | −94,583 | $44.54 | $4.21M | 3,610,376 |
| Advisors Llc Orbimed Director | Nov 24, 2025 | Sale(10b5-1 plan) | −94,583 | $44.54 | $4.21M | 3,610,376 |
| Peter Kolchinsky Director, 10% owner | Nov 21, 2025 | Sale | −6,440 | $39.50 | $254.38K | 2,198,082 |
| Peter Kolchinsky Director, 10% owner | Nov 21, 2025 | Sale | −9,924 | $39.50 | $392.00K | 650,307 |
| Peter Kolchinsky Director, 10% owner | Nov 21, 2025 | Sale | −1,210 | $39.50 | $47.80K | 6,897,623 |
Awards, option exercises, tax withholding and gifts are shown alongside open-market buys and sales. Each name links to the filing on SEC EDGAR.
Planned insider sales
Notices of proposed sale filed on Form 144 before shares are sold
| Seller | Filed | Shares | Market value | Planned sale | Acquired through |
|---|---|---|---|---|---|
| RA Capital Healthcare Fund, L.P. Director, 10% Stockholder | Sep 17, 2026 | 3,448,811 | $21.83M | Sep 17, 2026 | Private Transaction |
| Fitzpatrick Jennifer Officer | Jul 6, 2026 | 10,250 | $450.90K | Jul 6, 2026 | Exercise of Stock Options |
| OrbiMed Private Investments VIII, LP Shareholder | Jun 1, 2026 | 210,876 | $9.03M | May 29, 2026 | IPO |
| OrbiMed Private Investments VIII, LP Shareholder | May 29, 2026 | 1,082,480 | $46.33M | May 29, 2026 | IPO |
| Fitzpatrick Jennifer Officer | Mar 5, 2026 | 10,250 | $354.34K | Mar 5, 2026 | Exercise of Stock Options |
| Rise Fund Sling II, L.P. Stockholder | Jan 22, 2026 | 54,333 | $2.27M | Jan 22, 2026 | The shares of Common Stock reported herein were originally acquired by Seller upon the automatic conversion of shares of Preferred Stock of the Issuer into shares of Common Stock |
| Rise Fund Sling, L.P. Stockholder | Jan 22, 2026 | 195,667 | $8.17M | Jan 22, 2026 | The shares of Common Stock reported herein were originally acquired by Seller from Issuer and/or upon the automatic conversion of shares of Preferred Stock of the Issuer into shares of Common Stock. |
| R. Fitzpatrick Jennifer Officer | Dec 5, 2025 | 10,250 | $419.02K | Dec 5, 2025 | Exercise of Stock Options |
| OrbiMed Private Investments VIII, LP Shareholder | Nov 24, 2025 | 1,047,770 | $46.50M | Nov 24, 2025 | IPO |
| Partners Llc - Series A. Blackwell Director, 10% Stockholder | Nov 21, 2025 | 7,609 | $332.21K | Nov 21, 2025 | Private Transaction |
| RA Capital Nexus Fund, L.P. Director, 10% Stockholder | Nov 21, 2025 | 9,924 | $433.28K | Nov 21, 2025 | Private Transaction |
| RA Capital Nexus Fund III, L.P. Director, 10% Stockholder | Nov 21, 2025 | 6,440 | $281.17K | Nov 21, 2025 | Private Funding |
| Capital Healthcare Fund LP RA Director, 10% Stockholder | Nov 21, 2025 | 1,210 | $52.83K | Nov 21, 2025 | Private Transaction |
| RA Capital Nexus Fund III, L.P. Director, 10% Stockholder | Nov 20, 2025 | 1,313 | $51.13K | Nov 20, 2025 | Private Funding |
| RA Capital Nexus Fund, L.P. Director, 10% Stockholder | Nov 20, 2025 | 2,023 | $78.78K | Nov 20, 2025 | Private Transaction |