RA CAPITAL MANAGEMENT, L.P.

RA Capital's $9.44B March 2026 portfolio is the largest pure-play biotechnology vehicle in the 13F dataset reviewed to this point, and its $3.8B aggregate top-ten exposure reads as a concentrated late-stage therapeutics bet with a clear new direction: rare and genetic disease platforms. Ascendis Pharma (ASND) anchors the book at 24.9% ($2.35B), up $159M in the quarter, but the most significant new commitments were Spyglass Pharma (SGP, $208M initiated), Vaxcyte (PCVX, up $172M to $667M), Zai Lab ADR (ZLAB, $107M initiated), and Sarepta Therapeutics (SRPT, $85M initiated) — all rare-disease or precision-medicine developers with late-stage programs. Simultaneously, the fund fully exited two earlier convictions: Cidara Therapeutics (CDTX, $743M sold, the prior quarter's eighth-largest position) and Avidity Biosciences (RNA, $623M sold), both RNA-targeting or antifungal developers that have underperformed or de-risked into a different payoff structure. The 86-position portfolio shows 29 holdings unchanged through a volatile quarter, while 37 positions moved — a high churn rate consistent with an active biotech manager rotating around clinical catalysts. The fund's AUM declined $323M (from $9.76B to $9.44B), modest given the book's volatility profile. The whaleScore of 79.25 reflects scale; what distinguishes this filing is RA Capital's demonstrated willingness to exit entire positions at scale when the thesis evolves and to initiate equally large new ones.