Madison Avenue Partners, LP → Ultragenyx Pharmaceutical Inc. RARE

Stake: — Shares: — Class: Common Stock, $0.001 par value (the "Common Stock")

Composite Decision Signal · PASS (LOW BASE-RATE EDGE) Conviction Score: 22/100

Passive Schedule 13G filer baseline
Material 8-K governance/transaction event (Item 5.02 / 1.01 / 2.01) within ±30d
Moderate short days-to-cover (3.1 DTC)
Short interest building (+22.8% vs prior settlement)

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)

0 transactions

0 buys · 0 sales · 0 awards/exercises

Issuer Cluster

1 13D/G filings on this issuer

0 other filings besides this one

Filer Track Record

3 filings by this filer

2 other filings in the data moat

Short Interest · settle 2026-09-30

DTC 3.13

20,349,877 shares short · +22.8% vs prior

Other Filings by Madison Avenue Partners, LP

Filed	Form	Issuer	Stake	Shares
2026-06-23	SCHEDULE 13G	Lakefront Biotherapeutics NV GLPGF	—	—	view →
2021-05-27	SC	LEAF GROUP LTD.	—	—	view →

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