ZENAS BIOPHARMA (ZBIO) Institutional Ownership & Top Holders
The most recent SEC Form 13F filings (Q1 2026) show 4 hedge funds and institutional investors holding a combined 3.4M shares of ZENAS BIOPHARMA (ZBIO), valued at $67.0M. The median portfolio weight is 0.8%.
The latest institutional ownership changes for ZBIO show net buying, with the combined position up by 431K shares (14.4%) from the previous quarter.
Among 13F filers, the funds with the highest portfolio allocation to ZBIO are Fairmount (3.3% of its 13F portfolio), Exome Asset Management (0.9%), and EcoR1 Capital (0.7%). In Q1 2026, Exome Asset Management made the largest position increase (+0.9%).
Top 4 Institutional Holders in ZENAS BIOPHARMA (ZBIO), Ranked by Portfolio Weight
Based on the latest SEC Form 13F filings (Q1 2026).
| # | Fund | Shares | Market Value | Portfolio Weight |
|---|---|---|---|---|
| 1 | Fairmount | 2,359,025 | $46.1M | 3.3% |
| 2 | Exome Asset Management | 80,730 | $1.6M | 0.9% |
| 3 | EcoR1 Capital | 789,500 | $15.4M | 0.7% |
| 4 | Vestal Point Capital | 200,000 | $3.9M | 0.1% |
- 4Institutional investors
- 3,429,255Shares held (disclosed)
- $67.0M13F market value
- 0.8%Median portfolio weight
Ownership History
Quarter-by-quarter share count, market value, and portfolio conviction weight (up to 5 of the heaviest weight-by-portfolio funds) of ZBIO. Sourced from 13F filings; reflects long equity positions only.
Quarter-over-Quarter ActivityQ1 2026
The biggest weight-increase and weight-decrease changes among funds that hold ZBIO. Deltas compare the selected filing to the previous reporting quarter.
Top buyers
- Exome Asset Management+0.9% · +80,730 shares
- Vestal Point Capital+0.1% · +200,000 shares
- Fairmount+-2.8% · +150,000 shares
Top sellers
No notable sellers this quarter.
Ownership Statistics
- Funds holding
- 4
- Median weight
- 0.8%
- Largest holder
- Fairmount · 3.3%
- Smallest holder
- Vestal Point Capital · 0.1%
- Shares held
- 3,429,255 (+430,730)
All Institutional HoldersSortable · searchable
All institutional investors (Max 50) holding ZBIO in the selected quarter. Click a fund name to drill into its full 13F portfolio.
| 1 | Fairmount | 2,359,025 | $46.1M | 3.3% |
| 2 | Exome Asset Management | 80,730 | $1.6M | 0.9% |
| 3 | EcoR1 Capital | 789,500 | $15.4M | 0.7% |
| 4 | Vestal Point Capital | 200,000 | $3.9M | 0.1% |
Institutional Investor Count Over Time
Number of institutional investors disclosing a long position in ZENAS BIOPHARMA INC (ZBIO) each reporting quarter. Sourced from SEC Form 13F-HR filings.
Methodology & FAQ
Methodology: How We Track ZBIO Institutional Holdings
Our data is systematically aggregated directly from quarterly Form 13F-HR disclosures submitted to the U.S. Securities and Exchange Commission (SEC).
- Who Must File (Reporting Threshold): This dataset includes filings from U.S. institutional investment managers, hedge funds, mutual funds, university endowments, and family offices managing at least $100 million in Section 13(f) securities (including equities, options, convertibles, ETFs, and warrants).
- What is Included (Data Scope): We capture long positions in Section 13(f) securities for ZENAS BIOPHARMA INC (ZBIO). By SEC regulation, 13F filings do not require the disclosure of short positions, non-U.S. holdings, or OTC derivatives. Listed options are excluded from portfolio weight calculations to ensure comparability across filers.
- Portfolio Weight Explained (Metric Definition): “Portfolio Weight” shows how much of a fund's total reported 13F portfolio value (excluding listed options) is allocated to ZBIO on the specific reporting date.
- How to Use This Data (Interpretation): Quarter-over-quarter changes in shares and portfolio weight reflect a combination of active trading and market price movements. These are descriptive metrics of fund allocation, not explicit buy or sell signals.
How do you measure hedge fund conviction and institutional concentration in ZBIO?
We evaluate fund conviction by looking at portfolio weight rather than just absolute share count. By tracking how the largest holders —such as Fairmount , Exome Asset Management , and EcoR1 Capital as of Q1 2026— change their position sizing quarter-over-quarter, we help investors distinguish between deliberate position sizing changes and passive mark-to-market drift.
Does the ZBIO ownership data include short interest or options?
SEC Form 13F mandates the disclosure of long positions in Section 13(f) securities, which includes equities and listed options (put and call contracts), but excludes short interest, swaps, and OTC derivatives by regulatory design. On this platform, listed options are excluded from portfolio weight calculations to ensure comparability across filers.
Are family offices and university endowments included in this ZBIO data?
Yes. In addition to traditional hedge funds and large asset managers, any institutional entity exercising investment discretion over at least $100 million in Section 13(f) securities must file a Form 13F. This explicitly includes single-family offices and university endowments. If a qualifying family office or endowment holds ZBIO stock, their allocation is systematically aggregated alongside traditional fund data.
When is the institutional ownership data updated, and is there a reporting lag?
Institutional investment managers are required to file their Form 13F within 45 days after the end of a calendar quarter (the standard “T+45” window). Our platform re-ingests new filings from the SEC EDGAR database on a nightly cycle, typically within 24–48 hours of publication, providing a point-in-time snapshot of reported consensus positioning for ZBIO as of each filing date.