Bain Capital Life Sciences Investors, LLC

In its 13F for Q3 2025 (holdings as of September 30, 2025, filed November 14, 2025), Bain Capital Life Sciences Investors, LLC reported 20 stock positions worth $1.5 billion. Its top holding was Heartflow (HTFL) at 27.8% of the portfolio, followed by Newamsterdam Pharma (NAMS, 20.3%) and Cidara Therapeutics (CDTX, 19.2%). Compared with Q2 2025, it opened 1 new position, sold out of 3, added to 2 and reduced 3. The biggest buy was a new position in Heartflow (HTFL) and the biggest sale an exit from Nuvalent Class A (NUVL).

Most Recent 13F
Q2 2026
Location
Boston, MA
CIK
0001703031
Portfolio Value
$1.5B (Q3 2025)
SEC Filing
0001193125-25-283094 ↗ filed Nov 14, 2025

Holdings Value

0$500.0M$1.0B$1.5B$2.0B Q1 2024: $1.2B Q1 2024 Q2 2024: $910.0M Q2 2024 Q3 2024: $960.5M Q3 2024 Q4 2024: $848.7M Q4 2024 Q1 2025: $675.0M Q1 2025 Q2 2025: $798.5M Q2 2025 Q3 2025: $1.5B $1.5B Q3 2025 Q4 2025: $1.3B Q4 2025 Q1 2026: $1.1B Q1 2026 Q2 2026: $1.7B Q2 2026

Holdings 20 stocks · $1.5B
HTFL Heartflow Inc. 27.84% 12,448,158 $419.0M New
NAMS Newamsterdam Pharma Co. NV 20.26% 10,719,110 $304.9M No change
CDTX Cidara Therapeutics Inc. 19.22% 3,020,990 $289.3M Add +20.8%
PHVS Pharvaris NV 5.27% 3,181,275 $79.4M Reduce -3.7%
OLMA Olema Pharmaceuticals Inc. 4.45% 6,843,954 $67.0M No change
SVRA Savara Inc. 4.18% 17,600,621 $62.8M No change
DNTH Dianthus Therapeutics Inc. 3.44% 1,315,892 $51.8M Reduce -47.0%
SLDB Solid Biosciences Inc. 3.24% 7,911,669 $48.8M No change
UPB Upstream Bio Inc. 3.05% 2,439,538 $45.9M No change
RPID Rapid Micro Biosystems Inc. Class A 1.87% 8,434,560 $28.2M No change
TNGX Tango Therapeutics Inc. 1.51% 2,712,008 $22.8M No change
CABA Cabaletta Bio Inc. 1.50% 9,677,125 $22.6M No change
KYTX Kyverna Therapeutics Inc. 1.34% 3,368,370 $20.2M No change
ANNX Annexon Inc. 1.06% 5,249,069 $16.0M No change
XFOR X4 Pharmaceuticals Inc. 0.55% 2,436,588 $8.3M Add +332.1%
AVIR Atea Pharmaceuticals Inc. 0.48% 2,485,638 $7.2M No change
XLO Xilio Therapeutics Inc. 0.26% 4,566,817 $3.8M No change
MRSN Mersana Therapeutics Inc. 0.18% 346,545 $2.7M No change
CCCC C4 Therapeutics Inc. 0.16% 1,111,910 $2.5M No change
IPSC Century Therapeutics Inc. 0.12% 3,538,609 $1.8M Reduce -34.6%
Other holdings (1): bonds, preferreds, convertibles and warrants · $1.7M (not counted above)
SecurityClassShares / PrincipalValueChange
NAMSW Newamsterdam Pharma Co. NV-27 *W EXP 99/99/999 100,000$1.7MNo change

Total filed on the 13F, all lines: $1.5B.

Portfolio Sells Q2 2025 → Q3 2025
NUVL Nuvalent Inc. Class A Sold out 0.00% −13.83
IRON Disc Medicine Inc. Sold out 0.00% −3.87
DNTH Dianthus Therapeutics Inc. Reduce -47.0% 3.44% −2.35
PHVS Pharvaris NV Reduce -3.7% 5.27% −2.01
IPSC Century Therapeutics Inc. Reduce -34.6% 0.12% −0.26
IVVD Invivyd Inc. Sold out 0.00% −0.16

Portfolio Buys Q2 2025 → Q3 2025
HTFL Heartflow Inc. New 27.84% +27.84
CDTX Cidara Therapeutics Inc. Add +20.8% 19.22% +3.97
XFOR X4 Pharmaceuticals Inc. Add +332.1% 0.55% +0.42

All Filings

QuarterPositions13F Reported ValueTop Holdings
Q2 2026 20$1.7BKLRA, HTFL, NAMS, SVRA, ALKS
Q1 2026 19$1.1BHTFL, NAMS, OLMA, SVRA, PHVS
Q4 2025 18$1.3BHTFL, NAMS, OLMA, SVRA, PHVS
Q3 2025 20$1.5BHTFL, NAMS, CDTX, PHVS, OLMA
Q2 2025 22$798.5MNAMS, CDTX, NUVL, PHVS, DNTH
Q1 2025 23$675.0MNAMS, NUVL, PHVS, IRON, DNTH
Q4 2024 25$848.7MNAMS, NUVL, PHVS, IRON, DNTH
Q3 2024 23$960.5MNUVL, NAMS, IRON, DNTH, SVRA
Q2 2024 24$910.0MNUVL, NAMS, IRON, DNTH, PHVS
Q1 2024 25$1.2BNAMS, NUVL, DNTH, IRON, KYTX