Bain Capital Life Sciences Investors, LLC
In its 13F for Q2 2026 (holdings as of June 30, 2026, filed August 14, 2026), Bain Capital Life Sciences Investors, LLC reported 20 stock positions worth $1.7 billion. Its top holding was Kailera Therapeutics (KLRA) at 29.6% of the portfolio, followed by Heartflow (HTFL, 14.8%) and Newamsterdam Pharma (NAMS, 7.7%). Compared with Q1 2026, it opened 2 new positions, sold out of 1, added to 2 and reduced 7. The biggest buy was a new position in Kailera Therapeutics (KLRA) and the biggest sale Newamsterdam Pharma (NAMS, shares −48%).
- Most Recent 13F
- Q2 2026
- Location
- Boston, MA
- CIK
- 0001703031
- Portfolio Value
- $1.7B (Q2 2026)
- SEC Filing
- 0001193125-26-350470 ↗ filed Aug 14, 2026
Holdings Value
Holdings 20 stocks · $1.7B
| KLRA Kailera Therapeutics Inc. | 29.62% | 22,583,268 | $497.5M | New |
| HTFL Heartflow Inc. | 14.76% | 8,448,158 | $247.9M | Reduce -19.1% |
| NAMS Newamsterdam Pharma Co. NV | 7.68% | 3,806,566 | $129.0M | Reduce -47.9% |
| SVRA Savara Inc. | 6.45% | 17,600,621 | $108.4M | No change |
| ALKS Alkermes PLC | 6.04% | 1,937,938 | $101.5M | Add +217.7% |
| SLDB Solid Biosciences Inc. | 5.83% | 9,808,819 | $98.0M | No change |
| PHVS Pharvaris NV | 5.51% | 2,675,509 | $92.5M | No change |
| OLMA Olema Pharmaceuticals Inc. | 5.28% | 7,085,249 | $88.6M | Reduce -5.2% |
| COAG Hemab Therapeutics Holdings | 3.61% | 1,650,000 | $60.6M | New |
| CABA Cabaletta Bio Inc. | 3.19% | 17,241,445 | $53.6M | Add +78.2% |
| XFOR X4 Pharmaceuticals Inc. | 2.21% | 7,967,454 | $37.2M | No change |
| DNTH Dianthus Therapeutics Inc. | 2.10% | 362,470 | $35.3M | No change |
| CCCC C4 Therapeutics Inc. | 1.99% | 7,171,910 | $33.5M | No change |
| KYTX Kyverna Therapeutics Inc. | 1.53% | 2,885,000 | $25.7M | Reduce -7.2% |
| ANNX Annexon Inc. | 1.51% | 4,437,731 | $25.3M | Reduce -14.9% |
| RPID Rapid Micro Biosystems Inc. Class A | 0.87% | 8,434,560 | $14.6M | No change |
| IRON Disc Medicine Inc. | 0.61% | 141,234 | $10.3M | No change |
| AVIR Atea Pharmaceuticals Inc. | 0.57% | 2,075,639 | $9.7M | Reduce -12.1% |
| XLO Xilio Therapeutics Inc. | 0.38% | 664,021 | $6.4M | No change |
| UPB Upstream Bio Inc. | 0.25% | 600,949 | $4.2M | Reduce -30.7% |
Other holdings (1): bonds, preferreds, convertibles and warrants · $2.1M (not counted above)
| Security | Class | Shares / Principal | Value | Change |
|---|---|---|---|---|
| NAMSW Newamsterdam Pharma Co. NV-27 | *W EXP 99/99/999 | 99,999 | $2.1M | No change |
Total filed on the 13F, all lines: $1.7B.
Portfolio Sells Q1 2026 → Q2 2026
| NAMS Newamsterdam Pharma Co. NV | Reduce -47.9% | 7.68% | −13.45 |
| HTFL Heartflow Inc. | Reduce -19.1% | 14.76% | −8.21 |
| OLMA Olema Pharmaceuticals Inc. | Reduce -5.2% | 5.28% | −4.79 |
| CNTA Centessa Pharmaceuticals Ltd. | Sold out | 0.00% | −2.28 |
| ANNX Annexon Inc. | Reduce -14.9% | 1.51% | −1.10 |
| KYTX Kyverna Therapeutics Inc. | Reduce -7.2% | 1.53% | −0.89 |
| AVIR Atea Pharmaceuticals Inc. | Reduce -12.1% | 0.57% | −0.57 |
| UPB Upstream Bio Inc. | Reduce -30.7% | 0.25% | −0.46 |
Portfolio Buys Q1 2026 → Q2 2026
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 |