Sionna Therapeutics Inc
Held by 2 superinvestors (SION).
Educational data only — not investment advice. 13F positions are self-reported and can lag up to 45 days.
Ownership · 13F consensus
Who's buying it
Institutional ownership aggregated across funds — consensus strength and this quarter's moves. Describes actions, not advice.
2 superinvestors hold it · $129.2M combined
Largest holder Andreas Halvorsen
Held by 2 superinvestors of Sionna Therapeutics Inc (SION); this quarter 1 trimmed (as of 2026-03-31).
13F positions are self-reported and can lag up to 45 days. Informational only — not investment advice.
Next · is it cheap
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Browse all valued stocks, ranked by value bandSuperinvestors Holding This Security
- Value$128.1MWeight (prev→now)0.3% → 0.4%
- Value$1.1MWeight (prev→now)0.0% → 0.0% ▼
Ownership overview
Sionna Therapeutics Inc (SION) is held by 2 of the superinvestors tracked on Compounder, with a combined $129.2M in reported 13F value. The largest position belongs to Andreas Halvorsen, where it makes up 0.4% of the portfolio.
Other notable holders by value include Polen Capital (0.0% of its book).
Over the latest quarter, 0 of the tracked filers opened a new position in SION, 0 added to existing ones, 1 trimmed, and 0 sold out entirely.
Holder counts and values reflect the most recent SEC Form 13F filings, through the quarter ended 2026-03-31. Source: SEC EDGAR. A 13F shows only long US-listed positions and can lag the real portfolio by up to 45 days, so this is disclosed long ownership, not a complete picture.
Holders over time
Superinvestors holding this security over the last 5 quarters: 1 → 2.
Early quarters may understate holder counts due to data backfill — read the slope with care.
Sources· SEC EDGAR 13F as of 2026-03-31 · filed 2026-05-15
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