Bain Capital Life Sciences Investors, LLC In its 13F for Q4 2025 (holdings as of December 31, 2025, filed February 17, 2026), Bain Capital Life Sciences Investors, LLC reported 18 stock positions worth $1.3 billion . Its top holding was Heartflow (HTFL) at 27.8% of the portfolio, followed by Newamsterdam Pharma (NAMS, 19.7% ) and Olema Pharmaceuticals (OLMA, 16.3% ). Compared with Q3 2025, it sold out of 2, added to 4 and reduced 6. The biggest buy was Olema Pharmaceuticals (OLMA, shares +24% ) and the biggest sale an exit from Cidara Therapeutics (CDTX).
Location Boston, MA
CIK 0001703031
Portfolio Value $1.3B (Q4 2025) Holdings 18 stocks · $1.3B Holdings quarter Q2 2026 Q1 2026 Q4 2025 Q3 2025 Q2 2025 Q1 2025 Q4 2024 Q3 2024 Q2 2024 Q1 2024
Stock % Of Portfolio ▼ Shares Held Total Value Change vs Q3 2025 HTFL Heartflow Inc. 12,448,158 $362.9M No change NAMS Newamsterdam Pharma Co. NV 7,306,566 $256.3M Reduce -31.8% OLMA Olema Pharmaceuticals Inc. 8,508,641 $212.7M Add +24.3% SVRA Savara Inc. 17,600,621 $106.1M No change PHVS Pharvaris NV 2,802,081 $77.8M Reduce -11.9% SLDB Solid Biosciences Inc. 7,911,669 $44.6M No change UPB Upstream Bio Inc. 1,329,544 $36.1M Reduce -45.5% XFOR X4 Pharmaceuticals Inc. 7,967,454 $31.9M Add +227.0% DNTH Dianthus Therapeutics Inc. 743,592 $30.6M Reduce -43.5% KYTX Kyverna Therapeutics Inc. 3,110,000 $29.2M Reduce -7.7% ANNX Annexon Inc. 5,249,069 $26.4M No change RPID Rapid Micro Biosystems Inc. Class A 8,434,560 $24.5M No change CABA Cabaletta Bio Inc. 9,677,125 $21.2M No change CCCC C4 Therapeutics Inc. 7,171,910 $13.7M Add +545.0% MRSN Mersana Therapeutics Inc. 346,545 $10.0M No change AVIR Atea Pharmaceuticals Inc. 2,485,638 $8.9M No change TNGX Tango Therapeutics Inc. 653,493 $5.8M Reduce -75.9% XLO Xilio Therapeutics Inc. 7,372,686 $4.7M Add +61.4%
Other holdings (1): bonds, preferreds, convertibles and warrants · $2.3M (not counted above) Security Class Shares / Principal Value Change NAMSW Newamsterdam Pharma Co. NV-27 *W EXP 99/99/999 99,999 $2.3M Reduce 0.0%
Total filed on the 13F, all lines: $1.3B.
Portfolio Sells Q3 2025 → Q4 2025 Portfolio Sells quarter Q2 2026 Q1 2026 Q4 2025 Q3 2025 Q2 2025 Q1 2025 Q4 2024 Q3 2024 Q2 2024 Q1 2024
Stock Change vs Q3 2025 % Of Portfolio Change To Portfolio ▲ CDTX Cidara Therapeutics Inc. Sold out 0.00% −19.22 DNTH Dianthus Therapeutics Inc. Reduce -43.5% 2.35% −1.09 TNGX Tango Therapeutics Inc. Reduce -75.9% 0.44% −1.07 NAMS Newamsterdam Pharma Co. NV Reduce -31.8% 19.67% −0.59 UPB Upstream Bio Inc. Reduce -45.5% 2.77% −0.28 IPSC Century Therapeutics Inc. Sold out 0.00% −0.12 PHVS Pharvaris NV Reduce -11.9% 5.97% +0.69 KYTX Kyverna Therapeutics Inc. Reduce -7.7% 2.24% +0.90
Portfolio Buys Q3 2025 → Q4 2025 Portfolio Buys quarter Q2 2026 Q1 2026 Q4 2025 Q3 2025 Q2 2025 Q1 2025 Q4 2024 Q3 2024 Q2 2024 Q1 2024
Stock Change vs Q3 2025 % Of Portfolio Change To Portfolio ▼ OLMA Olema Pharmaceuticals Inc. Add +24.3% 16.32% +11.87 XFOR X4 Pharmaceuticals Inc. Add +227.0% 2.45% +1.89 CCCC C4 Therapeutics Inc. Add +545.0% 1.05% +0.89 XLO Xilio Therapeutics Inc. Add +61.4% 0.36% +0.11
Notes & Other Activity Q3 2025 → Q4 2025 Security Class Change vs Q3 2025 Shares / Principal Value ▼ NAMSW Newamsterdam Pharma Co. NV-27 *W EXP 99/99/999 Reduce 0.0% 99,999 $2.3M
Bonds, preferreds, convertibles and warrants; not part of the stock holdings or percentages above.
All Filings Quarter Positions 13F Reported Value Top Holdings Q2 2026 20 $1.7B KLRA, HTFL, NAMS, SVRA, ALKS Q1 2026 19 $1.1B HTFL, NAMS, OLMA, SVRA, PHVS Q4 2025 18 $1.3B HTFL, NAMS, OLMA, SVRA, PHVS Q3 2025 20 $1.5B HTFL, NAMS, CDTX, PHVS, OLMA Q2 2025 22 $798.5M NAMS, CDTX, NUVL, PHVS, DNTH Q1 2025 23 $675.0M NAMS, NUVL, PHVS, IRON, DNTH Q4 2024 25 $848.7M NAMS, NUVL, PHVS, IRON, DNTH Q3 2024 23 $960.5M NUVL, NAMS, IRON, DNTH, SVRA Q2 2024 24 $910.0M NUVL, NAMS, IRON, DNTH, PHVS Q1 2024 25 $1.2B NAMS, NUVL, DNTH, IRON, KYTX