Bain Capital Life Sciences Investors, LLC
In its 13F for Q1 2026 (holdings as of March 31, 2026, filed May 15, 2026), Bain Capital Life Sciences Investors, LLC reported 19 stock positions worth $1.1 billion. Its top holding was Heartflow (HTFL) at 23.0% of the portfolio, followed by Newamsterdam Pharma (NAMS, 21.1%) and Olema Pharmaceuticals (OLMA, 10.1%). Compared with Q4 2025, it opened 3 new positions, sold out of 2, added to 2 and reduced 7. The biggest buy was Solid Biosciences (SLDB, shares +24%) and the biggest sale Olema Pharmaceuticals (OLMA, shares −12%).
- Most Recent 13F
- Q2 2026
- Location
- Boston, MA
- CIK
- 0001703031
- Portfolio Value
- $1.1B (Q1 2026)
- SEC Filing
- 0001193125-26-226961 ↗ filed May 15, 2026
Holdings Value
Holdings 19 stocks · $1.1B
| HTFL Heartflow Inc. | 22.97% | 10,448,158 | $254.2M | Reduce -16.1% |
| NAMS Newamsterdam Pharma Co. NV | 21.13% | 7,306,566 | $233.9M | No change |
| OLMA Olema Pharmaceuticals Inc. | 10.07% | 7,473,238 | $111.4M | Reduce -12.2% |
| SVRA Savara Inc. | 8.68% | 17,600,621 | $96.1M | No change |
| PHVS Pharvaris NV | 6.83% | 2,675,509 | $75.6M | Reduce -4.5% |
| SLDB Solid Biosciences Inc. | 6.38% | 9,808,819 | $70.6M | Add +24.0% |
| XFOR X4 Pharmaceuticals Inc. | 2.97% | 7,967,454 | $32.9M | No change |
| DNTH Dianthus Therapeutics Inc. | 2.75% | 362,470 | $30.4M | Reduce -51.3% |
| ANNX Annexon Inc. | 2.61% | 5,212,674 | $28.9M | Reduce -0.7% |
| KYTX Kyverna Therapeutics Inc. | 2.42% | 3,110,000 | $26.8M | No change |
| CABA Cabaletta Bio Inc. | 2.35% | 9,677,125 | $26.0M | No change |
| CNTA Centessa Pharmaceuticals Ltd. | 2.28% | 635,000 | $25.2M | New |
| ALKS Alkermes PLC | 1.95% | 610,000 | $21.6M | New |
| RPID Rapid Micro Biosystems Inc. Class A | 1.73% | 8,434,560 | $19.1M | No change |
| CCCC C4 Therapeutics Inc. | 1.70% | 7,171,910 | $18.9M | No change |
| AVIR Atea Pharmaceuticals Inc. | 1.15% | 2,360,638 | $12.7M | Reduce -5.0% |
| IRON Disc Medicine Inc. | 0.82% | 141,234 | $9.0M | New |
| UPB Upstream Bio Inc. | 0.71% | 867,211 | $7.8M | Reduce -34.8% |
| XLO Xilio Therapeutics Inc. | 0.50% | 664,021 | $5.6M | Add +26.1% |
Other holdings (1): bonds, preferreds, convertibles and warrants · $2.0M (not counted above)
| Security | Class | Shares / Principal | Value | Change |
|---|---|---|---|---|
| NAMSW Newamsterdam Pharma Co. NV-27 | *W EXP 99/99/999 | 99,999 | $2.0M | No change |
Total filed on the 13F, all lines: $1.1B.
Portfolio Sells Q4 2025 → Q1 2026
| OLMA Olema Pharmaceuticals Inc. | Reduce -12.2% | 10.07% | −6.25 |
| HTFL Heartflow Inc. | Reduce -16.1% | 22.97% | −4.87 |
| UPB Upstream Bio Inc. | Reduce -34.8% | 0.71% | −2.06 |
| MRSN Mersana Therapeutics Inc. | Sold out | 0.00% | −0.77 |
| TNGX Tango Therapeutics Inc. | Sold out | 0.00% | −0.44 |
| DNTH Dianthus Therapeutics Inc. | Reduce -51.3% | 2.75% | +0.40 |
| AVIR Atea Pharmaceuticals Inc. | Reduce -5.0% | 1.15% | +0.47 |
| ANNX Annexon Inc. | Reduce -0.7% | 2.61% | +0.59 |
| PHVS Pharvaris NV | Reduce -4.5% | 6.83% | +0.86 |
Portfolio Buys Q4 2025 → Q1 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 |