SIONNA THERAPEUTICS INC (SION)
Institutional ownership reported to the SEC as of Q2 2026, across 7 quarters.
Institutions report 48,281,384 shares against 45,212,399 outstanding. Shares only - option lines are excluded, which is why this can be compared with the company at all. The count comes from the cover page of the company's own most recent report, so it is dated when that was filed rather than at quarter end. Over 100% because an adviser and a sub-adviser can both report the same shares, and both are counted.
Calls and puts are the parts of reported value carried in derivative lines rather than shares, and they point in opposite directions: a manager holding calls is positioned for the security, one holding puts against it - or hedging shares they already own, which is why index funds carry so many. Most sites add the two together and report one figure, which averages away the only interesting part.
Holders
| Filer | Value | Shares | Their book | Held | Change |
|---|---|---|---|---|---|
| RA CAPITAL MANAGEMENT, L.P. | $435.7M | 9,905,045 | 3.79% | 6q | HELD |
| TPG GP A, LLC | $285.7M | 6,494,962 | 5.71% | 6q | HELD |
| VIKING GLOBAL INVESTORS LP | $140.6M | 3,195,181 | 0.40% | 6q | HELD |
| Atlas Venture Life Science Advisors, LLC | $131.8M | 2,995,602 | 14.95% | 6q | HELD |
| ORBIMED ADVISORS LLC | $112.4M | 2,555,877 | 2.08% | 6q | -27.6%-$42.9M |
| ENAVATE SCIENCES GP, LLC | $109.0M | 2,478,030 | 31.56% | 6q | HELD |
| ADAGE CAPITAL PARTNERS GP, L.L.C. | $70.4M | 1,600,000 | 0.10% | 2q | +966.7%+$63.8M |
| BlackRock, Inc. | $64.9M | 1,474,769 | 0.00% | 6q | +13.8%+$7.9M |
| JPMORGAN CHASE & CO | $64.1M | 1,490,508 | 0.00% | 6q | +1.7%+$1.1M |
| JENNISON ASSOCIATES LLC | $51.6M | 1,172,133 | 0.03% | 6q | -19.2%-$12.3M |
| CITADEL ADVISORS LLC | $50.9M incl. $369.5K options PUT | 1,147,636 | 0.01% | 6q | -1.7%-$855.0K |
| VANGUARD CAPITAL MANAGEMENT LLC | $49.8M | 1,132,001 | 0.00% | 2q | +10.0%+$4.5M |
| STATE STREET CORP | $44.9M | 1,021,534 | 0.00% | 6q | +35.1%+$11.7M |
| PERCEPTIVE ADVISORS LLC | $39.8M | 905,000 | 0.60% | 6q | +37.4%+$10.8M |
| DEERFIELD MANAGEMENT COMPANY, L.P. | $30.0M | 680,916 | 0.31% | 6q | -29.8%-$12.7M |
| Siren, L.L.C. | $26.9M | 610,515 | 0.54% | 6q | +103.5%+$13.7M |
| PRICE T ROWE ASSOCIATES INC /MD/ | $21.0M | 478,016 | 0.00% | 6q | -36.8%-$12.2M |
| EVENTIDE ASSET MANAGEMENT, LLC | $20.9M | 474,981 | 0.28% | 3q | -26.4%-$7.5M |
| GEODE CAPITAL MANAGEMENT, LLC | $20.1M | 457,145 | 0.00% | 6q | +17.3%+$3.0M |
| BAKER BROS. ADVISORS LP | $17.6M | 400,000 | 0.09% | 6q | HELD |
| Casdin Capital, LLC | $17.6M | 400,000 | 0.88% | new | NEW |
| Kalehua Capital Management LLC | $17.3M | 394,144 | 5.53% | 3q | HELD |
| GOLDMAN SACHS GROUP INC | $17.1M | 388,810 | 0.00% | 6q | +47.7%+$5.5M |
| Driehaus Capital Management LLC | $17.0M | 385,447 | 0.10% | 6q | +403.0%+$13.6M |
| MILLENNIUM MANAGEMENT LLC | $14.3M incl. $2.1M options CALL+PUT | 276,733 | 0.01% | 6q | +96.8%+$7.0M |
| FRANKLIN RESOURCES INC | $12.8M | 290,113 | 0.00% | 6q | +65.3%+$5.0M |
| Aberdeen Group plc | $12.5M | 284,138 | 0.02% | 6q | -49.6%-$12.3M |
| FMR LLC | $12.2M | 278,292 | 0.00% | 4q | +241.9%+$8.7M |
| Candriam S.C.A. | $10.2M | 233,208 | 0.05% | 2q | -1.5%-$158.4K |
| VANGUARD PORTFOLIO MANAGEMENT LLC | $9.8M | 222,949 | 0.00% | 2q | +56.9%+$3.6M |
| Longaeva Partners L.P. | $8.6M | 196,352 | 0.19% | 4q | +1446.9%+$8.1M |
| Artisan Partners Limited Partnership | $8.3M | 189,498 | 0.01% | new | NEW |
| Ensign Peak Advisors, Inc | $8.1M | 184,532 | 0.01% | 3q | -27.8%-$3.1M |
| Soleus Capital Management, L.P. | $7.8M | 177,687 | 0.27% | 6q | -39.5%-$5.1M |
| NORTHERN TRUST CORP | $6.8M | 154,476 | 0.00% | 6q | +32.3%+$1.7M |
| MORGAN STANLEY | $6.6M | 151,047 | 0.00% | 6q | +13.5%+$792.9K |
| Sofinnova Investments, Inc. | $6.4M | 144,432 | 0.33% | new | NEW |
| Qube Research & Technologies Ltd | $6.2M | 140,309 | 0.01% | 2q | +232.2%+$4.3M |
| Alyeska Investment Group, L.P. | $6.0M | 136,222 | 0.02% | 6q | HELD |
| GordonMD Global Investments LP | $6.0M | 136,000 | 2.89% | 2q | HELD |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | $5.7M | 129,753 | 0.00% | 6q | +7.9%+$417.9K |
| Sio Capital Management, LLC | $5.6M | 127,808 | 0.93% | 2q | -56.6%-$7.3M |
| VANGUARD FIDUCIARY TRUST CO | $5.3M | 121,442 | 0.00% | 2q | +8.3%+$407.7K |
| Artia Global Partners LP | $5.3M | 119,741 | 0.97% | 3q | HELD |
| UBS Group AG | $5.1M | 116,206 | 0.00% | 6q | -21.3%-$1.4M |
| First Turn Management, LLC | $4.9M | 110,493 | 0.52% | new | NEW |
| CITIGROUP INC | $4.8M | 110,163 | 0.00% | 5q | +510.1%+$4.1M |
| Ikarian Capital, LLC | $4.7M PUT | options only | 0.51% | new | OPTIONS |
| D. E. Shaw & Co., Inc. | $4.5M | 101,644 | 0.00% | new | NEW |
| Rock Springs Capital Management LP | $4.4M | 99,429 | 0.21% | 6q | HELD |
| Walleye Capital LLC | $4.3M | 97,347 | 0.02% | 2q | +544.8%+$3.6M |
| Rhenman & Partners Asset Management AB | $4.3M | 97,100 | 0.40% | 2q | +11.0%+$422.3K |
| BANK OF AMERICA CORP /DE/ | $3.9M | 88,908 | 0.00% | 6q | +74.8%+$1.7M |
| AMERIPRISE FINANCIAL INC | $3.6M | 82,232 | 0.00% | 6q | HELD |
| Integral Health Asset Management, LLC | $3.3M | 75,000 | 0.13% | 2q | +50.0%+$1.1M |
| SUPERSTRING CAPITAL MANAGEMENT LP | $2.8M | 63,156 | 1.75% | 3q | -55.2%-$3.4M |
| STEMPOINT CAPITAL LP | $2.6M | 59,426 | 0.45% | 2q | -18.7%-$600.6K |
| DEUTSCHE BANK AG\ | $2.3M | 53,353 | 0.00% | 5q | +302.7%+$1.8M |
| SEVEN GRAND MANAGERS, LLC | $2.2M | 50,000 | 0.09% | 3q | HELD |
| Point72 Asset Management, L.P. | $2.2M | 49,328 | 0.00% | 2q | -63.9%-$3.8M |
| TD Asset Management Inc | $2.1M | 47,396 | 0.00% | 6q | -42.9%-$1.6M |
| ALPS ADVISORS INC | $2.0M | 45,525 | 0.01% | 3q | +24.3%+$391.4K |
| SILVERARC CAPITAL MANAGEMENT, LLC | $1.9M | 42,478 | 0.19% | 6q | +7.8%+$134.7K |
| Russell Investments Group, Ltd. | $1.9M | 42,258 | 0.00% | 4q | -12.7%-$271.0K |
| Bank of New York Mellon Corp | $1.8M | 41,586 | 0.00% | 5q | +23.1%+$343.5K |
| Nuveen, LLC | $1.8M | 41,259 | 0.00% | 5q | +73.8%+$770.9K |
| XTX Topco Ltd | $1.7M | 38,096 | 0.02% | 3q | +61.8%+$639.8K |
| WELLINGTON MANAGEMENT GROUP LLP | $1.6M | 37,365 | 0.00% | 4q | -18.9%-$383.3K |
| MUTUAL OF AMERICA CAPITAL MANAGEMENT LLC | $1.6M | 35,968 | 0.02% | new | NEW |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE | $1.6M | 35,420 | 0.00% | 6q | -45.0%-$1.3M |
| BOOTHBAY FUND MANAGEMENT, LLC | $1.4M PUT | options only | 0.02% | new | OPTIONS |
| BNP PARIBAS FINANCIAL MARKETS | $1.4M | 31,803 | 0.00% | 5q | -21.6%-$385.7K |
| Ishara Investments LP | $1.4M | 123,000 | 0.99% | 2q | +150.0%+$810.3K |
| Swiss National Bank | $1.2M | 27,000 | 0.00% | new | NEW |
| Quadrature Capital Ltd | $1.1M | 26,023 | 0.01% | new | NEW |
| Trexquant Investment LP | $1.0M | 23,810 | 0.01% | new | NEW |
| NEW YORK STATE COMMON RETIREMENT FUND | $1.0M | 23,586 | 0.00% | 5q | +345.0%+$804.4K |
| ALLIANCEBERNSTEIN L.P. | $1.0M | 25,450 | 0.00% | 3q | +55.1%+$362.4K |
| TUDOR INVESTMENT CORP ET AL | $993.1K | 22,575 | 0.00% | new | NEW |
| RHUMBLINE ADVISERS | $981.4K | 22,309 | 0.00% | 5q | +21.9%+$176.0K |
| Maven Securities LTD | $879.8K | 20,000 | 0.02% | 2q | -20.0%-$219.9K |
| LOS ANGELES CAPITAL MANAGEMENT LLC | $820.2K | 18,645 | 0.00% | 3q | +353.0%+$639.1K |
| Susquehanna Portfolio Strategies, LLC | $793.3K | 18,034 | 0.01% | new | NEW |
| Rafferty Asset Management, LLC | $792.0K | 18,004 | 0.00% | 3q | -18.7%-$181.8K |
| Shay Capital LLC | $791.8K | 18,000 | 0.05% | new | NEW |
| WELLS FARGO & COMPANY/MN | $740.0K | 16,821 | 0.00% | 5q | +185.4%+$480.7K |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | $695.0K CALL+PUT | options only | 0.00% | 2q | OPTIONS |
| Engineers Gate Manager LP | $686.4K | 15,603 | 0.01% | new | NEW |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM | $653.3K | 14,852 | 0.00% | 5q | +1611.1%+$615.2K |
| KENNEDY CAPITAL MANAGEMENT LLC | $555.2K | 12,621 | 0.01% | 3q | +2.7%+$14.8K |
| MARSHALL WACE, LLP | $554.2K | 12,599 | 0.00% | new | NEW |
| Invesco Ltd. | $546.3K | 12,418 | 0.00% | 3q | +15.1%+$71.7K |
| MetLife Investment Management, LLC | $482.7K | 10,972 | 0.00% | 5q | +28.1%+$105.9K |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC | $467.3K | 10,622 | 0.00% | 2q | +9056.9%+$462.2K |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. | $463.4K | 10,582 | 0.00% | 5q | +15.2%+$61.2K |
| Jump Financial, LLC | $460.7K | 10,473 | 0.00% | new | NEW |
| VANGUARD ASSET MANAGEMENT, Ltd | $419.4K | 9,535 | 0.00% | new | NEW |
| PROFUND ADVISORS LLC | $402.1K | 9,140 | 0.01% | 3q | -8.0%-$35.1K |
| Virtus Investment Advisers, LLC | $400.7K | 9,109 | 0.09% | 5q | +42.9%+$120.3K |
| Legal & General Group Plc | $397.8K | 9,044 | 0.00% | 5q | +531.6%+$334.9K |
Five percent filings
Anyone crossing 5% of a company must say so within days - far sooner than the next quarterly holdings report. A 13D declares an intent to influence the company; a 13G is the passive version. See all activist filings →
| Filed | Form | Filer | % of class |
|---|---|---|---|
| 2026-09-21 | 13D/A | RA Capital Management, L.P.with 4 co-filers | 14.3% |
What the company announced
Form 8-K filings from the last 120 days, showing only the items worth a reader's attention. Earnings releases, exhibit attachments and general disclosures are filed constantly and are left out. Filed is when the SEC received it; event is the date the company says the thing happened.
| Filed | Event date | What | Source |
|---|---|---|---|
| 2026-09-14 | 2026-09-09 | Directors or officers departed or appointed Exit or disposal costs | filing |
What the insiders did
Open market purchases and sales reported on Form 4 in the last 180 days. Grants, option exercises and shares surrendered to cover tax are left out: they are compensation rather than a decision to buy or sell. Where a broker filled one order in tranches the lines are summed, because it was one decision.
Officers and directors
| Date | Insider | Role | Side | Shares | Value |
|---|---|---|---|---|---|
| 2026-05-11 | Thompson Peter A. | Director | Sold | 184,639 | $8.5M |
| 2026-06-30 | Thompson Peter A. | Director | Sold | 115,844 | $5.3M |
| 2026-05-08 | Thompson Peter A. | Director | Sold | 59,767 | $2.7M |
Ten percent owners and entities
Usually an institution that crossed a reporting threshold, or a company taking a strategic stake, rather than an individual with a view.
| Date | Insider | Role | Side | Shares | Value |
|---|---|---|---|---|---|
| 2026-09-17 | RA CAPITAL MANAGEMENT, L.P. | Director, 10% owner | Sold | 3,448,811 | $21.8M ×2 |
| 2026-05-11 | ORBIMED ADVISORS LLC | Director | Sold | 184,639 | $8.5M |
| 2026-06-30 | ORBIMED ADVISORS LLC | Director | Sold | 115,844 | $5.3M |
| 2026-05-08 | ORBIMED ADVISORS LLC | Director | Sold | 59,767 | $2.7M |
Quarter by quarter
Coverage begins with the quarter ending 2018-12-31. Earlier filings exist only as occasional late amendments, too sparse to describe a market, so they are not shown.
| Quarter | Holders | Value | Shares | New | Added | Trimmed | Options |
|---|---|---|---|---|---|---|---|
| Q3 2026 | 22 | $6.3M | 1,199,057 | 11 | 8 | 2 | 0.0% |
| Q2 2026 | 151 | $2.1B | 48,281,384 | 38 | 55 | 41 | 0.5% |
| Q1 2026 | 121 | $1.8B | 45,640,921 | 27 | 40 | 29 | 0.0% |
| Q4 2025 | 101 | $1.8B | 43,950,895 | 28 | 39 | 20 | 0.0% |
| Q3 2025 | 78 | $1.3B | 44,819,190 | 19 | 20 | 18 | 0.0% |
| Q2 2025 | 65 | $753.8M | 43,448,451 | 26 | 18 | 10 | 0.0% |
| Q1 2025 | 47 | $434.1M | 41,491,947 | 47 | 0 | 0 | 0.0% |