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SCHEDULE Filed 2025-11-07 Event 2025-11-05 SEC 0001346824-25-000045 →

RA CAPITAL MANAGEMENT, L.P. → Sionna Therapeutics, Inc. SION

Stake: 22.60% Shares: 10,071,712 CUSIP: 829401108 Class: Common Stock, $0.001 par value per share
Composite Decision Signal · PASS (LOW BASE-RATE EDGE) Conviction Score: 19/100 · Filer 90d Win Rate: 0% · Hist. 90d Edge: +0.0%
  • Filer track record (20 filings): 0% 90d win rate, +0.0% 90d edge
  • High conviction ownership stake (22.6%)
  • Held by 1 tracked 13F institutional manager
  • 8 NPORT-P mutual funds holding CUSIP
  • Moderate short days-to-cover (3.7 DTC)

Item 4 — Purpose of Transaction

Not extracted from this filing — typically because it's an amendment (13D/A) and Item 4 is unchanged from the parent filing. Read the raw SEC filing →

Cross-References

Insider Activity (last 365d)
24 transactions
1 buys · 22 sales · 1 awards/exercises
Issuer Cluster
2 13D/G filings on this issuer
1 other filing besides this one
Filer Track Record
88 filings by this filer
87 other filings in the data moat
Short Interest · settle 2026-10-15
DTC 3.74
3,676,508 shares short · -3.2% vs prior

Institutional Consensus · 2026-06-30

Held by elite portfolio managers
1 holder · $140.56M
Viking Global

Post-Filing Returns · since 2025-11-05 on SION

+1 day
0.0%
+5 days
0.0%
+30 days
0.0%
+60 days
0.0%
+90 days
0.0%
+180 days
0.0%

Anchor price 44.93 on closest trading day on/after 2025-11-05. Source: Yahoo Finance daily adj_close (split + dividend adjusted).

Form 4 Insider Transactions · last 365d

DateInsiderRoleTypeSharesPriceValue
2026-05-11 ORBIMED ADVISORS LLC director Sale 184,639 $46.22 $8.53M
2026-05-11 Thompson Peter A. director Sale 184,639 $46.22 $8.53M
2026-05-08 ORBIMED ADVISORS LLC director Sale 59,767 $44.58 $2.66M
2026-05-08 Thompson Peter A. director Sale 59,767 $44.58 $2.66M
2026-05-07 Thompson Peter A. director Sale 48,546 $44.61 $2.17M
2026-05-07 ORBIMED ADVISORS LLC director Sale 48,546 $44.61 $2.17M
2026-04-18 ORBIMED ADVISORS LLC director Sale 2,948 $44.52 $131K
2026-04-18 Thompson Peter A. director Sale 2,948 $44.52 $131K
2026-04-17 Thompson Peter A. director Sale 52,397 $44.68 $2.34M
2026-04-17 ORBIMED ADVISORS LLC director Sale 52,397 $44.68 $2.34M
2026-04-16 ORBIMED ADVISORS LLC director Sale 226,906 $45.34 $10.29M
2026-04-16 Thompson Peter A. director Sale 226,906 $45.34 $10.29M
2026-04-15 ORBIMED ADVISORS LLC director Sale 235,863 $44.64 $10.53M
2026-04-15 Thompson Peter A. director Sale 235,863 $44.64 $10.53M
2026-04-14 Thompson Peter A. director Sale 47,814 $44.51 $2.13M
2026-04-14 ORBIMED ADVISORS LLC director Sale 47,814 $44.51 $2.13M
2026-03-05 Fitzpatrick Jennifer officer Option exercise 10,250 $6.11 $63K
2026-03-05 Fitzpatrick Jennifer officer Sale 10,250 $33.86 $347K
2026-02-03 ORBIMED ADVISORS LLC director Sale 29,063 $44.58 $1.30M
2026-02-03 Thompson Peter A. director Sale 29,063 $44.58 $1.30M
2026-02-02 Thompson Peter A. director Sale 1,890 $44.57 $84K
2026-02-02 ORBIMED ADVISORS LLC director Sale 1,890 $44.57 $84K
2026-01-22 TPG GP A, LLC 10%+ owner Sale 250,000 $40.00 $10.00M
2026-01-02 McKee Charlotte officer Award 155,700 $39.21 $6.10M

Other 13D/G Filings on Sionna Therapeutics, Inc.

FiledFormFilerStakeShares
2026-09-21 SCHEDULE 13D/A RA CAPITAL MANAGEMENT, L.P. 14.30% 6,476,193 view →

Other Filings by RA CAPITAL MANAGEMENT, L.P.

FiledFormIssuerStakeShares
2026-10-26 SCHEDULE 13G Alector, Inc. — — view →
2026-10-22 SCHEDULE 13G Frazier Life Sciences Acquisition Corp. II — — view →
2026-09-22 SCHEDULE 13G BetterLife Pharma Inc. — — view →
2026-09-21 SCHEDULE 13D/A SIONNA THERAPEUTICS, INC. 14.30% 6,476,193 view →
2026-09-17 SCHEDULE 13D/A TYRA BIOSCIENCES, INC. — 14,130,492 view →
2026-09-03 SCHEDULE 13G JATT III Acquisition Corp — — view →
2026-08-17 SCHEDULE 13G Latigo Biotherapeutics, Inc. — — view →
2026-08-14 SCHEDULE 13D/A SEPTERNA, INC. — 5,525,324 view →
2026-08-11 SCHEDULE 13D/A Wave Life Sciences, Inc. — 34,314,406 view →
2026-08-10 SCHEDULE 13D/A SAB Biotherapeutics, Inc. — 9,609,852 view →
2026-07-23 SCHEDULE 13D/A ARTIVA BIOTHERAPEUTICS, INC. — 18,415,956 view →
2026-07-22 SCHEDULE 13D/A Freenome, Inc. — 15,367,270 view →
2026-07-21 SCHEDULE 13D/A VOR BIOPHARMA INC. — 12,937,855 view →
2026-07-20 SCHEDULE 13G Agenus Inc. — — view →
2026-07-07 SCHEDULE 13D/A Climb Bio, Inc. CLYM 33.00% 23,249,186 view →
2026-07-02 SCHEDULE 13D/A WEREWOLF THERAPEUTICS, INC. HOWL 4.10% 1,985,541 view →
2026-06-26 SCHEDULE 13D/A WEREWOLF THERAPEUTICS, INC. HOWL 6.00% 2,915,742 view →
2026-06-24 SCHEDULE 13D/A SOLID BIOSCIENCES INC. SLDB — 12,036,126 view →
2026-06-22 SCHEDULE 13D/A WEREWOLF THERAPEUTICS, INC. HOWL — 3,654,307 view →
2026-06-18 SCHEDULE 13D Parabilis Medicines, Inc. PBLS 23.80% 28,933,371 view →
Showing 20 of 87

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