Zenas BioPharma, Inc.
ZBIO- Exchange
- Nasdaq
- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001953926
No open-market purchases or sales by Zenas BioPharma, Inc. insiders were filed in the last 90 days; 144 institutions reported holding it in 13F filings for Q2 2026, worth $1.55B in total; no superinvestor holds it.
Holders of 5% or more of ZBIO
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Zenas BioPharma, Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| FMR LLC | 13G/A | 14.30%7.65M shares | +3.30 ppfrom 11.00% | May 12, 20254 filings | Feb 5, 2026 | SEC |
| InnoCare Pharma Inc. | 13G/A | 10.40%7.00M shares | +1.00 ppfrom 9.40% | Oct 15, 20252 filings | Sep 8, 2026 | SEC |
| Wellington Management Group LLP | 13G | 10.10%6.57M shares | New | Sep 8, 20261 filing | Sep 8, 2026 | SEC |
| Sr One Capital Management, LLC | 13D/A | 7.70%5.04M shares | −1.70 ppfrom 9.40% | Oct 14, 20252 filings | Aug 17, 2026 | SEC |
| Moulder Leon O Jr | 13D | 5.09%3.22M shares | +0.30 ppfrom 4.79% | Jun 6, 20255 filings | May 5, 2026 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
19 Schedule 13D and 13G filings on Zenas BioPharma, Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Sep 8, 20267:39 AM ET | Wellington Management Group LLPand 3 others | 13G | 10.10%6.57M shares | New | Aug 31, 2026 | SEC |
| Sep 8, 20266:49 AM ET | InnoCare Pharma Inc.and 2 others | 13G/A | 10.40%7.00M shares | +1.00 ppfrom 9.40% | Aug 26, 2026 | SEC |
| Aug 19, 20266:49 PM ET | Enavate Sciences GP, LLCand 1 other | 13D/A | 4.90%3.25M shares | −2.40 ppfrom 7.30%Below 5% | Aug 19, 2026 | SEC |
| Aug 17, 20266:59 PM ET | Sr One Capital Management, LLCand 7 others | 13D/A | 7.70%5.04M shares | −1.70 ppfrom 9.40% | Aug 13, 2026 | SEC |
| May 5, 20264:15 PM ET | Moulder Leon O Jrand 2 others | 13D | 5.09%3.22M shares | +0.30 ppfrom 4.79% | Apr 29, 2026 | SEC |
| Apr 2, 20265:44 PM ET | Moulder Leon O Jrand 2 others | 13D/A | 4.79%3.03M shares | −0.37 ppfrom 5.16%Below 5% | Mar 31, 2026 | SEC |
| Feb 5, 20261:43 PM ET | FMR LLCand 1 other | 13G/A | 14.30%7.65M shares | +3.30 ppfrom 11.00% | Dec 31, 2025 | SEC |
| Jan 14, 20264:30 PM ET | Moulder Leon O Jrand 2 others | 13D | 5.16%2.81M shares | +0.36 ppfrom 4.80% | Jan 7, 2026 | SEC |
| Nov 14, 20256:29 PM ET | Novo Holdings A/S | 13G/A | 4.70%2.00M shares | −0.60 ppfrom 5.30%Below 5% | Sep 30, 2025 | SEC |
| Oct 15, 20256:11 AM ET | InnoCare Pharma Inc.and 2 others | 13G | 9.40%5.00M shares | New | Oct 7, 2025 | SEC |
| Oct 14, 20255:29 PM ET | Enavate Sciences GP, LLCand 1 other | 13D/A | 7.30%3.92M shares | – | Oct 9, 2025 | SEC |
| Oct 14, 20255:29 PM ET | Sr One Capital Management, LLCand 7 others | 13D/A | 9.40%5.04M shares | – | Oct 9, 2025 | SEC |
| Oct 14, 20259:35 AM ET | Longitude Capital Partners IV, LLCand 5 others | 13D/A | 4.90%2.63M shares | –Below 5% | Oct 9, 2025 | SEC |
| Oct 9, 20255:15 PM ET | Moulder Leon O Jrand 2 others | 13D/A | 4.80%2.59M shares | −0.20 ppfrom 5.00%Below 5% | Oct 7, 2025 | SEC |
| Sep 8, 202511:46 AM ET | FMR LLCand 1 other | 13G/A | 11.00%4.64M shares | +3.10 ppfrom 7.90% | Aug 29, 2025 | SEC |
| Aug 6, 202512:19 PM ET | FMR LLCand 1 other | 13G/A | 7.90%3.32M shares | +1.10 ppfrom 6.80% | Jun 30, 2025 | SEC |
| Jun 6, 20254:10 PM ET | Moulder Leon O Jrand 1 other | 13D | 5.00%2.10M shares | New | May 30, 2025 | SEC |
| May 12, 202510:20 AM ET | FMR LLCand 1 other | 13G/A | 6.80%2.85M shares | – | Mar 31, 2025 | SEC |
| Apr 1, 20259:47 PM ET | Novo Holdings A/S | 13G | 5.30%2.21M shares | New | Mar 25, 2025 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Zenas BioPharma, Inc. shares.
No Form 144 notices for Zenas BioPharma, Inc. are on file.