Q2 2026 13F · SEC CIK 1703031
Bain Capital Life Sciences Investors, LLC
Asset managerFiled 2026-08-14 for Q2 2026. Open the filing ↗ · All SEC filings ↗
- Reported 13F value
- $1.7B
- Reported positions
- 21
- Top holdings a year, 3 yrs
- +50.1%
- Average holding period
- 1.9 yrs
Bain Capital Life Sciences Investors, LLC is an asset manager that reported 21 positions worth $1.7B in its Q2 2026 13F, filed 2026-08-14. Its largest holdings were Kailera Therapeutics Inc (KLRA, 29.6%), Heartflow Inc (HTFL, 14.7%), Newamsterdam Pharma Company (NAMS, 7.7%). A portfolio copying its top holdings returned 50.1% a year over the last 3 years, against 20.4% for the S&P 500.
Bain Capital Life Sciences Investors, LLC holdings all 21 positions.
Weights are shares of the filer's total reported 13F value, compared with Q1 2026. Share changes may reflect splits; weight changes also reflect price moves. A 13F shows long US-listed positions only, up to 135 days after the fact.
| Stock | % of 13F value | Share change | Reported value |
|---|---|---|---|
| KLRAKailera Therapeutics Inc | 29.6% | — | $497.5M |
| HTFLHeartflow Inc | 14.7% | -19.1% | $247.9M |
| NAMSNewamsterdam Pharma Company | 7.7% | -47.9% | $129.0M |
| SVRASavara Inc | 6.4% | +0.0% | $108.4M |
| ALKSAlkermes PLC | 6.0% | +217.7% | $101.5M |
| SLDBSolid Bioscience Inc. | 5.8% | +0.0% | $98.0M |
| PHVSPharvaris N V | 5.5% | +0.0% | $92.5M |
| OLMAOlema Pharmaceuticals Inc | 5.3% | -5.2% | $88.6M |
| COAGHemab Therapeutics Holdings Inc | 3.6% | — | $60.6M |
| CABACabaletta Bio Inc | 3.2% | +78.2% | $53.6M |
| XFORX4 Pharmaceuticals Inc | 2.2% | +0.0% | $37.2M |
| DNTHDianthus Therapeutics Inc | 2.1% | +0.0% | $35.3M |
| CCCCC4 Therapeutics Inc | 2.0% | +0.0% | $33.5M |
| KYTXKyverna Therapeutics Inc. | 1.5% | -7.2% | $25.7M |
| ANNXAnnexon Inc | 1.5% | -14.9% | $25.3M |
| RPIDRapid Micro Biosystems Inc | 0.9% | +0.0% | $14.6M |
| IRONDisc Medicine Inc | 0.6% | +0.0% | $10.3M |
| AVIRAtea Pharmaceuticals Inc | 0.6% | -12.1% | $9.7M |
| XLOXilio Therapeutics Inc | 0.4% | +0.0% | $6.4M |
| UPBUpstream Bio Inc | 0.2% | -30.7% | $4.2M |
| NAMSWNewamsterdam Pharma Company | 0.1% | +0.0% | $2.1M |
What Bain Capital Life Sciences Investors, LLC bought and sold in Q2 2026, against Q1 2026.
New positions
- KLRA Kailera Therapeutics Inc29.6% of 13F
- COAG Hemab Therapeutics Holdings Inc3.6% of 13F
Added to
- ALKS Alkermes PLC+217.7% shares
- CABA Cabaletta Bio Inc+78.2% shares
Reduced
- NAMS Newamsterdam Pharma Company-47.9% shares
- UPB Upstream Bio Inc-30.7% shares
- HTFL Heartflow Inc-19.1% shares
- ANNX Annexon Inc-14.9% shares
- AVIR Atea Pharmaceuticals Inc-12.1% shares
- KYTX Kyverna Therapeutics Inc.-7.2% shares
- OLMA Olema Pharmaceuticals Inc-5.2% shares
Sold out
Share counts compared with the Q1 2026 13F; a split also changes share counts.
How the holdings did against the S&P 500.
- 1 year
- +125.8% /yr
- S&P 500 +20.1%
- 3 years
- +50.1% /yr
- S&P 500 +20.4%
- 5 years
- +14.8% /yr
- S&P 500 +11.6%
A portfolio of the filer's 20 largest 13F positions, weighted by value and rebuilt each quarter on the day the filing became public. 13Fs show long US-listed positions only, so this is an estimate of the stock picks, not the fund's reported returns.
Reported 13F value by quarter.
| Quarter | 13F value | Positions |
|---|---|---|
| Q2 2026 | $1.7B | 21 |
| Q1 2026 | $1.1B | 20 |
| Q4 2025 | $1.3B | 19 |
| Q3 2025 | $1.5B | 21 |
| Q2 2025 | $799.3M | 23 |
| Q1 2025 | $675.9M | 24 |
| Q4 2024 | $850.1M | 26 |
| Q3 2024 | $961.2M | 24 |
| Q2 2024 | $910.8M | 25 |
| Q1 2024 | $1.2B | 26 |
| Q4 2023 | $1.0B | 27 |
| Q3 2023 | $894.2M | 31 |
Questions about Bain Capital Life Sciences Investors, LLC's portfolio
What stocks does Bain Capital Life Sciences Investors, LLC own?
Bain Capital Life Sciences Investors, LLC's latest 13F, for Q2 2026 and filed Aug 14, 2026, lists 21 positions worth $1.7B. The largest are Kailera Therapeutics Inc (KLRA) at 29.6%, Heartflow Inc (HTFL) at 14.7%, Newamsterdam Pharma Company (NAMS) at 7.7%, Savara Inc (SVRA) at 6.4% and Alkermes PLC (ALKS) at 6.0%.
What did Bain Capital Life Sciences Investors, LLC buy last quarter?
In Q2 2026, Bain Capital Life Sciences Investors, LLC added a new position in Kailera Therapeutics Inc (KLRA), a new position in Hemab Therapeutics Holdings Inc (COAG), Alkermes PLC (ALKS) (+217.7% shares) and Cabaletta Bio Inc (CABA) (+78.2% shares), compared with its Q1 2026 filing.
What did Bain Capital Life Sciences Investors, LLC sell last quarter?
In Q2 2026, Bain Capital Life Sciences Investors, LLC sold all of Centessa Pharmaceuticals PLC (CNTA), Newamsterdam Pharma Company (NAMS) (-47.9% shares), Upstream Bio Inc (UPB) (-30.7% shares) and Heartflow Inc (HTFL) (-19.1% shares), compared with its Q1 2026 filing.
How has Bain Capital Life Sciences Investors, LLC's portfolio performed?
A portfolio copying Bain Capital Life Sciences Investors, LLC's 20 largest 13F holdings each quarter, from the day each filing was public, returned +50.1% a year over the last 3 years, against +20.4% for the S&P 500. Over 1 year: +125.8% against +20.1%. Over 5 years: +14.8% a year against +11.6%.
When is Bain Capital Life Sciences Investors, LLC's next 13F filing due?
13F filings are due 45 days after each quarter ends. Bain Capital Life Sciences Investors, LLC's filing for the quarter ending Sep 30, 2026 is due by Nov 14, 2026; this page updates the day after it is published.