BAKER BROS. ADVISORS LP
"13F equity value" = market value of this filer's US-listed long equity positions only. It excludes cash, bonds, non-US and short positions, so it understates a fund's true assets under management — often by a lot.
13F holdings are disclosed ~45 days after quarter-end, and they never reveal when within the quarter a fund actually bought. So any 13F-based summary is structurally late and blurred — this applies to every fund, including this one.
We backtested copying it anyway. Buying this fund's new positions the day each filing went public, over 27 quarters, returned +4.8% per quarter — versus +2.3% per quarter from simply owning every 13F stock. It beat that baseline in only 37.0% of quarters (excess t = -1.34, not statistically significant). Its filings tell you what it bought — not what you should buy.
Quarterly compounding, invested quarters only · entry 47 days after quarter-end (when 13F data becomes public)
Top 20 holdings of 84 · 2026 Q1
| Ticker | Value | Weight | QoQ |
|---|---|---|---|
| INCY | $2.9B | | HOLD |
| ONC | $2.6B | | HOLD |
| INSM | $1.2B | | ADD |
| MDGL | $1.1B | | HOLD |
| ACAD | $955M | | HOLD |
| RVMD | $929M | | HOLD |
| CELC | $904M | | HOLD |
| KOD | $759M | | HOLD |
| KYMR | $721M | | HOLD |
| SMMT | $690M | | HOLD |
| PRAX | $565M | | ADD |
| RYTM | $487M | | HOLD |
| ALKS | $354M | | HOLD |
| GRAL | $208M | | ADD |
| EWTX | $207M | | HOLD |
| IONS | $154M | | ADD |
| KNSA | $136M | | HOLD |
| IMVT | $136M | | HOLD |
| ROIV | $135M | | TRIM |
| IDYA | $131M | | ADD |
QoQ vs previous quarter's share count · NEW = new position · ADD/TRIM = ±2% shares · HOLD = unchanged.
New positions in 2026 Q1
Method & Limitations
Method: a "new position" = held this quarter, absent last quarter (options excluded; stocks with <50 prior holders excluded to filter spin-off artifacts). Entry 47 days after quarter-end — the first day the public could act on the filing. Benchmark = equal-weighted universe of all 13F-held stocks. Limitations: quarterly snapshots can't see intra-quarter trades; survivorship bias — funds that shut down are absent, which flatters the sample. Statistics, not advice.