RA CAPITAL MANAGEMENT, L.P.
"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 28 quarters, returned +1.6% per quarter — versus +2.8% per quarter from simply owning every 13F stock. It beat that baseline in only 46.4% of quarters (excess t = -0.79, 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 85 · 2026 Q1
| Ticker | Value | Weight | QoQ |
|---|---|---|---|
| ASND | $2.4B | | HOLD |
| PCVX | $667M | | ADD |
| RYTM | $580M | | HOLD |
| TYRA | $467M | | HOLD |
| SION | $397M | | HOLD |
| EWTX | $328M | | HOLD |
| NAMS | $306M | | HOLD |
| NUVL | $260M | | ADD |
| DNTH | $219M | | ADD |
| MLYS | $208M | | ADD |
| SGP | $208M | | NEW |
| WVE | $196M | | ADD |
| SEPN | $168M | | HOLD |
| IRON | $157M | | ADD |
| JANX | $156M | | HOLD |
| BCRX | $151M | | HOLD |
| BCAX | $144M | | ADD |
| PRAX | $120M | | HOLD |
| GHRS | $108M | | HOLD |
| ZLAB | $107M | | NEW |
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.