Rock Springs Capital Management LP
Position in ZBIO — Zenas BioPharma, Inc.
CIK 1595725
Baltimore, MD
Position in ZBIO
as of Mar 31, 2026
· filed May 15, 2026
Position Value
$9,815,605
-$8,414,810 QoQ
Shares Held
502,077
0.0% QoQ
Ownership
0.795%
of shares outstanding
% of Portfolio
0.58%
of 13F equity value
Holder Rank
—
not a current holder
Holding Since
Sep 2024
7 quarters on record
Voting authority
Sole 100.ToString("F0")%
Shared 0.ToString("F0")%
None 0.ToString("F0")%
Common Shares in ZBIO Over Time
Shares Held
Position Value (USD)
Position in Biotechnology
Healthcare · as of Mar 31, 2026Rock Springs Capital Management LP holds $1,246,050,197 across 66 Biotechnology names. ZBIO ranks #35 (0.8% of the industry book) .
| # | Ticker | Company | Shares | Value (USD) | Open |
|---|---|---|---|---|---|
| 1 | RVMD |
Revolution Medicines, Inc.
|
1,209,465 | $117,620,471 | |
| 2 | MDGL |
Madrigal Pharmaceuticals, Inc.
|
170,999 | $89,512,846 | |
| 3 | MIRM |
Mirum Pharmaceuticals, Inc.
|
811,294 | $74,947,339 | |
| 4 | ARGX |
Argenx SE
|
98,500 | $71,929,625 | |
| 5 | RYTM |
Rhythm Pharmaceuticals, Inc.
|
689,748 | $59,987,383 | |
| 6 | INSM |
INSMED Inc
|
314,300 | $51,394,336 | |
| 7 | ASND |
Ascendis Pharma A/S
|
194,000 | $44,373,620 | |
| 8 | XENE |
Xenon Pharmaceuticals Inc.
|
763,020 | $44,369,613 |
All Filings in ZBIO
Export CSV
7 filing rows on record
| Report Date | Value (USD) | Shares | Type | Discretion | Filed | |
|---|---|---|---|---|---|---|
| 2026-03-31 | $9,815,605 | 502,077 | Shares | Sole | 2026-05-15 | |
| 2025-12-31 | $18,230,415 | 502,077 | Shares | Sole | 2026-02-17 | |
| 2025-09-30 | $12,891,029 | 580,677 | Shares | Sole | 2025-11-14 | |
| 2025-06-30 | $6,206,125 | 640,467 | Shares | Sole | 2025-08-14 | |
| 2025-03-31 | $6,941,469 | 878,667 | Shares | Sole | 2025-05-15 | |
| 2024-12-31 | $7,196,282 | 878,667 | Shares | Sole | 2025-02-14 | |
| 2024-09-30 | $14,867,045 | 878,667 | Shares | Sole | 2024-11-14 | |
| No filing history on record for this holder in this stock. | ||||||