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Of the 13 tracked institutions holding SION, 6 have a 3-year clone track record — 6 of them beat the S&P. Average holder's clone alpha: +4.5pt. It's a gauge of who owns the name, not just how many.
Among the 13 tracked institutional investors we monitor, SION (SIONNA THERAPEUTICS INC) is held with a combined value of $922.56M across 21,048,850 shares. The largest holder is RA CAPITAL MANAGEMENT, L.P. with a position worth $435.72M (3.79% of their portfolio). 6 funds increased their holdings. 4 funds reduced their position.
Total Institutional Value
$922.56M
Total Shares Held
21,048,850
Institutional Holders
13
Ranked by estimated dollars moved (share change × implied price). 13F data lags up to 45 days.
| # | Fund | Value↓ | Portfolio % | Change |
|---|---|---|---|---|
| 1 | RA CAPITAL MANAGEMENT, L.P. | $435.72M | 3.79% | - |
| 2 | VIKING GLOBAL INVESTORS LP | $140.56M | 0.40% | - |
| 3 | ADAGE CAPITAL PARTNERS GP, L.L.C. | $70.38M | 0.10% | +966.7% |
| 4 | BlackRock, Inc. | $64.88M | 0.00% | +13.8% |
| 5 | CITADEL ADVISORS LLC | $50.48M | 0.03% | -1.7% |
| 6 | VANGUARD GROUP INC | $48.75M | 0.00% | +3.7% |
| 7 | STATE STREET CORP | $44.94M | 0.00% | +35.1% |
| 8 | PRICE T ROWE ASSOCIATES INC /MD/ | $21.03M | 0.00% | -36.8% |
| 9 | BAKER BROS. ADVISORS LP | $17.60M | 0.09% | - |
| 10 | FMR LLC | $12.24M | 0.00% | +241.9% |
SEC Schedule 13D (activist) and 13G (passive) filings for SION. Filed when an investor acquires 5%+ ownership.
As of the latest SEC 13F filings, RA CAPITAL MANAGEMENT, L.P. is the largest institutional holder of SION with a position worth $435.72M, representing 3.79% of their portfolio. In total, 13 institutional investors hold SION with a combined value of $922.56M.
Institutional investors hold $922.56M worth of SION stock across 13 positions. The largest institutional holder is RA CAPITAL MANAGEMENT, L.P. with $435.72M in holdings.
A 13F filing is a quarterly report required by the SEC from institutional investment managers with over $100 million in assets. It discloses their holdings in U.S. equities. For SION, these filings reveal which major funds are accumulating or reducing positions, providing insights into institutional sentiment.
Get notified when hedge funds change their SION positions.
Alpha = the manager's 3-year clone return minus the S&P 500. A skilled roster is a stronger tell than a crowded one — though even skilled managers' edge doesn't reliably survive the 13F disclosure lag. Why →
Last Close
$4.91
2026-10-02
YTD
-87.5%
1% of 52-week range
