Rock Springs Capital ZBIO Position
Active4-Fund ConvergenceRock Springs Capital trimmed their position in Zenas BioPharma, Inc. (ZBIO) in Q4 2025, holding $18.2M worth of shares across 502,077 shares.
The position was first reported in Q3 2024 and has been tracked across 6 quarterly 13F filings.
ZBIO is a convergence signal: 4 specialist biotech funds hold this stock, suggesting high institutional conviction.
There is an upcoming Phase 3 readout for Obexelimab in 75 days (Jun 30, 2026), making the timing of Rock Springs's position particularly relevant.
Short interest stands at 21.1% of float with 13.0 days to cover, indicating significant bearish positioning against Rock Springs's long thesis.
4 insider purchases totaling $5.5M have been filed in the last 90 days, providing an additional conviction signal.
About Zenas BioPharma, Inc.
Zenas BioPharma, Inc., a clinical-stage biopharmaceutical company, engages in the development and commercialization of transformative immunology-based therapies. Its lead product candidate is obexelimab, a bifunctional monoclonal antibody for various indications, including immunoglobulin G4-related disease, multiple sclerosis, systemic lupus erythematosus, and warm autoimmune hemolytic anemia. The company also develops ZB002, an anti-TNFa monoclonal antibody; ZB004, a cytotoxic T-lymphocyte-associated antigen 4-immunoglobulin fusion; ZB001, an anti-insulin-like growth factor-1 receptor monoclonal antibody; and ZB005, an anti-active complement component 1s monoclonal antibody. Zenas BioPharma, Inc. was formerly known as Zenas BioPharma (Cayman) Limited and changed its name to Zenas BioPharma, Inc. in August 2023. The company was incorporated in 2019 and is based in Waltham, Massachusetts.
Full company profile →Short Interest
21.1%
13.0 days to cover
Insider Buys (90d)
4
$5.5M total
Rock Springs Capital ZBIO Position History
Frequently Asked Questions
Does Rock Springs Capital own ZBIO?
Yes. As of Q4 2025, Rock Springs Capital holds 502,077 shares of Zenas BioPharma, Inc. (ZBIO) valued at $18.2M. This data comes from their SEC 13F filing.
How many hedge funds own ZBIO?
4 specialist biotech hedge funds currently hold ZBIO, including Deerfield Management, EcoR1 Capital, Perceptive Advisors. When 3 or more specialist funds hold the same stock, BiotechEdge flags it as a convergence signal.
When did Rock Springs Capital first buy ZBIO?
Rock Springs Capital's position in ZBIO was first reported in Q3 2024. 13F filings are reported with a 45-day delay, so the actual purchase may have occurred earlier in the quarter.
Is Rock Springs Capital's ZBIO position increasing or decreasing?
Rock Springs Capital trimmed their ZBIO position in the most recent quarter, reducing by 78,600 shares.
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