SIONNA THERAPEUTICS INC (SION) Top 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 March 31, 2026. The institutional investors covered on this page collectively reported approximately $1.73B 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 $397.09M in its March 31, 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 $363.81M, representing an estimated loss of -8.38% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 78% 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, Orbimed Advisors Llc, 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
120
Total Reported Value
$1.73B
Largest Holder
Ra Capital Management, L.P.
Largest Position
$397.09M
Insider Transactions (90d)
0
Latest Filing Quarter
Q1 2026
New Institutional Positions
132
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. | 4.21% | 9,905,045 | $397,093,254 | $363,812,303 | -$33,280,951 | -8.38% | |
| Tpg Gp A, Llc | 7.08% | 6,494,962 | $260,383,027 | $238,559,954 | -$21,823,073 | -8.38% | |
| Orbimed Advisors Llc | 3.09% | 3,530,702 | $141,545,843 | $129,682,684 | -$11,863,159 | -8.38% | |
| Viking Global Investors | Ole Andreas Halvorsen | 0.36% | 3,195,181 | $128,094,806 | $117,358,998 | -$10,735,808 | -8.38% |
| Atlas Venture Life Science Advisors, Llc | 15.20% | 2,995,602 | $120,093,684 | $110,028,461 | -$10,065,223 | -8.38% | |
| Enavate Sciences Gp, Llc | 28.26% | 2,478,030 | $99,344,223 | $91,018,042 | -$8,326,181 | -8.38% | |
| Jennison Associates Llc | 0.04% | 1,451,220 | $58,179,411 | $53,303,311 | -$4,876,100 | -8.38% | |
| Blackrock, Inc. | 0.00% | 1,295,867 | $51,951,309 | $47,597,195 | -$4,354,114 | -8.38% | |
| Citadel Advisors Llc | 0.03% | 1,166,931 | $46,782,264 | $42,861,376 | -$3,920,888 | -8.38% | |
| Vanguard Capital Management Llc | 0.00% | 1,029,497 | $41,272,535 | $37,813,425 | -$3,459,110 | -8.38% | |
| Deerfield Management Company, L.P. | 0.46% | 970,590 | $38,910,953 | $35,649,771 | -$3,261,182 | -8.38% | |
| State Street Corp | 0.00% | 756,227 | $30,317,140 | $27,776,218 | -$2,540,922 | -8.38% | |
| Perceptive Advisors Llc | 0.52% | 658,439 | $26,396,820 | $24,184,464 | -$2,212,356 | -8.38% | |
| Eventide Asset Management, Llc | 0.43% | 645,530 | $25,875,888 | $23,710,317 | -$2,165,571 | -8.37% | |
| Aberdeen Group Plc | 0.04% | 564,175 | $22,617,776 | $20,722,148 | -$1,895,628 | -8.38% | |
| Baker Bros. Advisors Lp | 0.09% | 400,000 | $16,036,000 | $14,692,000 | -$1,344,000 | -8.38% | |
| Geode Capital Management, Llc | 0.00% | 389,872 | $15,633,527 | $14,319,999 | -$1,313,528 | -8.40% | |
| Siren, L.L.C. | 0.33% | 300,000 | $12,027,000 | $11,019,000 | -$1,008,000 | -8.38% | |
| Sio Capital Management, Llc | 1.70% | 294,340 | $11,800,091 | $10,811,108 | -$988,983 | -8.38% | |
| Soleus Capital Management, L.P. | 0.48% | 293,500 | $11,766,415 | $10,780,255 | -$986,160 | -8.38% | |
| Goldman Sachs Group Inc | 0.00% | 263,174 | $10,550,646 | $9,666,381 | -$884,265 | -8.38% | |
| Ensign Peak Advisors, Inc | 0.02% | 255,636 | $10,248,447 | $9,389,510 | -$858,937 | -8.38% | |
| Candriam S.C.A. | 0.05% | 236,813 | $9,493,833 | $8,698,141 | -$795,692 | -8.38% | |
| Kalehua Capital Management Llc | 6.66% | 197,072 | $7,900,616 | $7,238,455 | -$662,161 | -8.38% | |
| Franklin Resources Inc | 0.00% | 175,483 | $7,035,113 | $6,445,491 | -$589,622 | -8.38% | |
| Adage Capital Partners Gp, L.L.C. | 0.01% | 150,000 | $6,013,500 | $5,509,500 | -$504,000 | -8.38% | |
| Ubs Group Ag | 0.00% | 147,641 | $5,918,928 | $5,422,854 | -$496,074 | -8.38% | |
| Vanguard Portfolio Management Llc | 0.00% | 142,081 | $5,696,027 | $5,218,635 | -$477,392 | -8.38% | |
| Superstring Capital Management Lp | 4.04% | 141,024 | $5,653,652 | $5,179,812 | -$473,840 | -8.38% | |
| Millennium Management Llc | 0.00% | 140,641 | $5,638,298 | $5,165,744 | -$472,554 | -8.38% | |
| Point72 Asset Management, L.P. | 0.01% | 136,549 | $5,474,249 | $5,015,445 | -$458,804 | -8.38% | |
| Alyeska Investment Group, L.P. | 0.02% | 136,222 | $5,461,140 | $5,003,434 | -$457,706 | -8.38% | |
| Gordonmd Global Investments Lp | 3.80% | 136,000 | $5,452,240 | $4,995,280 | -$456,960 | -8.38% | |
| Morgan Stanley | 0.00% | 133,023 | $5,332,893 | $4,885,935 | -$446,958 | -8.38% | |
| Charles Schwab Investment Management Inc | 0.00% | 120,253 | $4,820,943 | $4,416,893 | -$404,050 | -8.38% | |
| Artia Global Partners Lp | 1.08% | 119,741 | $4,800,417 | $4,398,087 | -$402,330 | -8.38% | |
| Northern Trust Corp | 0.00% | 116,776 | $4,681,551 | $4,289,182 | -$392,369 | -8.38% | |
| Vanguard Fiduciary Trust Co | 0.00% | 112,175 | $4,497,096 | $4,120,188 | -$376,908 | -8.38% | |
| Rock Springs Capital Management Lp | 0.23% | 99,429 | $3,986,109 | $3,652,027 | -$334,082 | -8.38% | |
| Rhenman & Partners Asset Management Ab | 0.43% | 87,500 | $3,507,875 | $3,213,875 | -$294,000 | -8.38% | |
| Td Asset Management Inc | 0.00% | 82,996 | $3,327,310 | $3,048,443 | -$278,867 | -8.38% | |
| Ameriprise Financial Inc | 0.00% | 81,974 | $3,286,338 | $3,010,905 | -$275,433 | -8.38% | |
| Fmr Llc | 0.00% | 81,395 | $3,263,126 | $2,989,638 | -$273,488 | -8.38% | |
| Driehaus Capital Management Llc | 0.02% | 76,633 | $3,072,217 | $2,814,730 | -$257,487 | -8.38% | |
| Manufacturers Life Insurance Company, The | 0.00% | 64,458 | $2,584,121 | $2,367,542 | -$216,579 | -8.38% | |
| Bank Of America Corp | 0.00% | 50,870 | $2,039,378 | $1,868,455 | -$170,923 | -8.38% | |
| Integral Health Asset Management, Llc | 0.11% | 50,000 | $2,004,500 | $1,836,500 | -$168,000 | -8.38% | |
| Seven Grand Managers, Llc | 0.13% | 50,000 | $2,004,500 | $1,836,500 | -$168,000 | -8.38% | |
| Ishara Investments Lp | 1.99% | 49,200 | $1,972,428 | $1,807,116 | -$165,312 | -8.38% | |
| Russell Investments Group, Ltd. | 0.00% | 48,419 | $1,941,133 | $1,778,430 | -$162,703 | -8.38% |
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.