SIONNA THERAPEUTICS INC (SION) Institutional Shareholders
SIONNA THERAPEUTICS INC (SION) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026. The institutional investors covered on this page collectively reported approximately $2.10B in SION holdings during the latest filing period.
Ra Capital Management, L.P. is currently the largest disclosed institutional shareholder of SION tracked by InsiderSet, reporting ownership valued at approximately $435.72M in its June 30, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $71.12M, representing an estimated loss of -83.68% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 70% of the total disclosed SION value among the investors covered in this analysis. Major shareholders include Ra Capital Management, L.P., Tpg Gp A, Llc, Viking Global Investors, and several other long-term asset managers with concentrated positions in SIONNA THERAPEUTICS INC (SION).
This page ranks the largest institutional SION shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
142
Total Reported Value
$2.10B
Largest Holder
Ra Capital Management, L.P.
Largest Position
$435.72M
Insider Transactions (90d)
10
Latest Filing Quarter
Q2 2026
New Institutional Positions
139
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Ra Capital Management, L.P. | 3.79% | 9,905,045 | $435,722,930 | $71,118,223 | -$364,604,707 | -83.68% | |
| Tpg Gp A, Llc | 5.71% | 6,494,962 | $285,713,378 | $46,633,827 | -$239,079,551 | -83.68% | |
| Viking Global Investors | Ole Andreas Halvorsen | 0.40% | 3,195,181 | $140,556,012 | $22,941,400 | -$117,614,612 | -83.68% |
| Atlas Venture Life Science Advisors, Llc | 14.95% | 2,995,602 | $131,776,532 | $21,508,422 | -$110,268,110 | -83.68% | |
| Orbimed Advisors Llc | 2.13% | 2,555,877 | $112,433,029 | $18,351,197 | -$94,081,832 | -83.68% | |
| Enavate Sciences Gp, Llc | 31.56% | 2,478,030 | $109,008,540 | $17,792,255 | -$91,216,285 | -83.68% | |
| Adage Capital Partners Gp, L.L.C. | 0.10% | 1,600,000 | $70,384,000 | $11,488,000 | -$58,896,000 | -83.68% | |
| Blackrock, Inc. | 0.00% | 1,474,769 | $64,875,089 | $10,588,841 | -$54,286,248 | -83.68% | |
| Jpmorgan Chase & Co | 0.00% | 1,490,508 | $64,085,673 | $10,701,847 | -$53,383,826 | -83.30% | |
| Jennison Associates Llc | 0.03% | 1,172,133 | $51,562,131 | $8,415,915 | -$43,146,216 | -83.68% | |
| Citadel Advisors Llc | 0.03% | 1,147,636 | $50,484,507 | $8,240,026 | -$42,244,481 | -83.68% | |
| Vanguard Capital Management Llc | 0.00% | 1,132,001 | $49,796,724 | $8,127,767 | -$41,668,957 | -83.68% | |
| State Street Corp | 0.00% | 1,021,534 | $44,937,281 | $7,334,614 | -$37,602,667 | -83.68% | |
| Perceptive Advisors Llc | 0.62% | 905,000 | $39,810,950 | $6,497,900 | -$33,313,050 | -83.68% | |
| Deerfield Management Company, L.P. | 0.31% | 680,916 | $29,953,495 | $4,888,977 | -$25,064,518 | -83.68% | |
| Siren, L.L.C. | 0.55% | 610,515 | $26,856,555 | $4,383,498 | -$22,473,057 | -83.68% | |
| Price T Rowe Associates Inc | 0.00% | 478,016 | $21,029,000 | $3,432,155 | -$17,596,845 | -83.68% | |
| Eventide Asset Management, Llc | 0.28% | 474,981 | $20,894,402 | $3,410,364 | -$17,484,038 | -83.68% | |
| Geode Capital Management, Llc | 0.00% | 457,145 | $20,113,984 | $3,282,301 | -$16,831,683 | -83.68% | |
| Baker Bros. Advisors Lp | 0.09% | 400,000 | $17,596,000 | $2,872,000 | -$14,724,000 | -83.68% | |
| Casdin Capital, Llc | 0.88% | 400,000 | $17,596,000 | $2,872,000 | -$14,724,000 | -83.68% | |
| Goldman Sachs Group Inc | 0.00% | 388,810 | $17,103,752 | $2,791,656 | -$14,312,096 | -83.68% | |
| Driehaus Capital Management Llc | 0.10% | 385,447 | $16,955,814 | $2,767,509 | -$14,188,305 | -83.68% | |
| Aberdeen Group Plc | 0.02% | 284,138 | $12,499,231 | $2,040,111 | -$10,459,120 | -83.68% | |
| Fmr Llc | 0.00% | 278,292 | $12,242,065 | $1,998,137 | -$10,243,928 | -83.68% | |
| Millennium Management Llc | 0.01% | 276,733 | $12,173,485 | $1,986,943 | -$10,186,542 | -83.68% | |
| Candriam S.C.A. | 0.05% | 233,208 | $10,248,950 | $1,674,433 | -$8,574,517 | -83.66% | |
| Ensign Peak Advisors, Inc | 0.02% | 255,636 | $10,248,447 | $1,835,466 | -$8,412,981 | -82.09% | |
| Vanguard Portfolio Management Llc | 0.00% | 222,949 | $9,807,527 | $1,600,774 | -$8,206,753 | -83.68% | |
| Kalehua Capital Management Llc | 4.98% | 197,072 | $8,669,197 | $1,414,977 | -$7,254,220 | -83.68% | |
| Longaeva Partners L.P. | 0.25% | 196,352 | $8,637,524 | $1,409,807 | -$7,227,717 | -83.68% | |
| Artisan Partners Limited Partnership | 0.01% | 189,498 | $8,336,017 | $1,360,596 | -$6,975,421 | -83.68% | |
| Soleus Capital Management, L.P. | 0.27% | 177,687 | $7,816,451 | $1,275,793 | -$6,540,658 | -83.68% | |
| Northern Trust Corp | 0.00% | 154,476 | $6,795,399 | $1,109,138 | -$5,686,261 | -83.68% | |
| Morgan Stanley | 0.00% | 151,047 | $6,644,558 | $1,084,517 | -$5,560,041 | -83.68% | |
| Sofinnova Investments, Inc. | 0.34% | 144,432 | $6,353,564 | $1,037,022 | -$5,316,542 | -83.68% | |
| Qube Research & Technologies Ltd | 0.01% | 140,309 | $6,172,193 | $1,007,419 | -$5,164,774 | -83.68% | |
| Alyeska Investment Group, L.P. | 0.02% | 136,222 | $5,992,406 | $978,074 | -$5,014,332 | -83.68% | |
| Gordonmd Global Investments Lp | 2.89% | 136,000 | $5,982,640 | $976,480 | -$5,006,160 | -83.68% | |
| Charles Schwab Investment Management Inc | 0.00% | 129,753 | $5,707,834 | $931,627 | -$4,776,207 | -83.68% | |
| Sio Capital Management, Llc | 0.96% | 127,808 | $5,622,274 | $917,661 | -$4,704,613 | -83.68% | |
| Vanguard Fiduciary Trust Co | 0.00% | 121,442 | $5,342,234 | $871,954 | -$4,470,280 | -83.68% | |
| Artia Global Partners Lp | 1.00% | 119,741 | $5,267,407 | $859,740 | -$4,407,667 | -83.68% | |
| Ubs Group Ag | 0.00% | 116,206 | $5,111,902 | $834,359 | -$4,277,543 | -83.68% | |
| First Turn Management, Llc | 0.52% | 110,493 | $4,860,587 | $793,340 | -$4,067,247 | -83.68% | |
| Citigroup Inc | 0.00% | 110,163 | $4,846,070 | $790,970 | -$4,055,100 | -83.68% | |
| D. E. Shaw & Co., Inc. | 0.00% | 101,644 | $4,471,320 | $729,804 | -$3,741,516 | -83.68% | |
| Rock Springs Capital Management Lp | 0.21% | 99,429 | $4,373,882 | $713,900 | -$3,659,982 | -83.68% | |
| Walleye Capital Llc | 0.02% | 97,347 | $4,282,295 | $698,951 | -$3,583,344 | -83.68% | |
| Rhenman & Partners Asset Management Ab | 0.40% | 97,100 | $4,271,429 | $697,178 | -$3,574,251 | -83.68% |
Frequently asked questions about SION
Who owns the most SION stock?
The largest holders of SION are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for SIONNA THERAPEUTICS INC (SION).
Is SION widely held by superinvestors?
Many widely followed stocks like SION appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly SION is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.