CIK: 0001703031
Total reported value
$1.1B
Reporting period: 2026-03-31 · Number of holdings: 20
Bain Capital Life Sciences Investors, LLC disclosed 20 holdings in its latest 13F filing for the period ending 2026-03-31, with total reported value of $1.1B and a quarterly turnover rate of 33.7%.
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Bain Capital Life Sciences Investors, LLC's disclosed holdings carry a Herfindahl concentration index of 0.129 — mathematically equivalent to about 8 equally-sized positions, well below its 20 actual disclosed holdings. That gap points to a strategy built around a small core of high-conviction bets rather than broad diversification.
Position sizes vary widely across the portfolio (a coefficient of variation of 1.29), with a handful of outsized bets alongside many smaller positions.
Recent activity leans toward adding more aggressively to already-large existing positions than to newly initiated ones (a 2.0 percentage-point tilt) — a pattern consistent with a momentum-following approach.
Sector classification currently covers about 2% of this portfolio's disclosed value; the remainder includes holdings (e.g. unmapped tickers, options, or other security types) not yet covered by our sector mapping.
Trim OLMA
-12.2% -$101.3M
Trim HTFL
-16.1% -$108.7M
Add SLDB
+24.0% $26.0M
Trim UPB
-34.8% -$28.3M
Add NAMS
0.0% -$22.4M
Add PHVS
-4.5% -$2.2M
| # | Ticker | Issuer | Asset Subclass | Weight | Weight Change | Shares Change | 4Q Trend |
|---|---|---|---|---|---|---|---|
| 1 | HTFL | Heartflow INC | Stock-Other | 22.93% | -4.86% | -16.07% | |
| 2 | NAMS | NewAmsterdam Pharma Company N.V. | Stock-Other | 21.09% | +1.46% | — | |
| 3 | OLMA | Olema Pharmaceuticals INC | Stock-Other | 10.05% | -6.24% | -12.17% | |
| 4 | SVRA | Savara INC | Stock-Other | 8.67% | +0.54% | — | |
| 5 | PHVS | Pharvaris N.V. | Stock-Other | 6.82% | +0.86% | -4.52% | |
| 6 | SLDB | Solid Biosciences INC | Stock-Other | 6.37% | +2.95% | +23.98% | |
| 7 | XFOR | X4 Pharmaceuticals INC | Stock-Other | 2.97% | +0.53% | — | |
| 8 | DNTH | Dianthus Therapeutics INC | Stock-Other | 2.74% | +0.39% | -51.25% | |
| 9 | ANNX | Annexon INC | Stock-Other | 2.60% | +0.58% | -0.69% | |
| 10 | KYTX | Kyverna Therapeutics INC | Stock-Other | 2.42% | +0.18% | — | |
| 11 | CABA | Cabaletta Bio INC | Stock-Other | 2.35% | +0.73% | — | |
| 12 | 260 | Centessa Pharmaceuticals-adr | Stock-Other | 2.27% | +2.27% | NEW | |
| 13 | ALKS | Alkermes plc | Stock-Healthcare | 1.95% | +1.95% | NEW | |
| 14 | RPID | Rapid Micro Biosystems Inc-a | Stock-Other | 1.73% | -0.14% | — | |
| 15 | CCCC | C4 Therapeutics INC | Stock-Other | 1.70% | +0.65% | — | |
| 16 | AVIR | Atea Pharmaceuticals INC | Stock-Other | 1.15% | +0.47% | -5.03% | |
| 17 | IRON | Disc Medicine INC | Stock-Other | 0.81% | +0.81% | NEW | |
| 18 | UPB | Upstream Bio INC | Stock-Other | 0.70% | -2.06% | -34.77% | |
| 19 | XLO | Xilio Therapeutics INC | Stock-Other | 0.50% | +0.50% | NEW | |
| 20 | ✓ | Newamsterdam Pharma Company | Stock-Other | 0.18% | — | — |
Performance for Q3 2026
+0.7%
Performance Last 4 Quarters
+68.6%
Based on 54% of reported portfolio value with available pricing
| Period | Holdings | Total value | Stability | Top holdings |
|---|---|---|---|---|
| 2026-03-31 | 20 | $1.1B | 34 | |
| 2025-12-31 | 19 | $1.3B | 50 | |
| 2025-09-30 | 21 | $1.5B | 100 | |
| 2025-06-30 | 23 | $799.3M | 0 | |
| 2025-03-31 | 24 | $675.9M | 100 | |
| 2024-12-31 | 26 | $850.1M | 0 | |
| 2024-09-30 | 24 | $961.2M | 0 | |
| 2024-06-30 | 25 | $910.8M | 0 | |
| 2024-03-31 | 26 | $1.2B | 0 | |
| 2023-12-31 | 27 | $1.0B | 0 | |
| 2023-09-30 | 31 | $894.2M | 0 | |
| 2023-06-30 | 32 | $971.0M | 0 | |
| 2023-03-31 | 34 | $800.1M | 0 | |
| 2022-12-31 | 33 | $894.8M | 0 | |
| 2022-09-30 | 33 | $837.8M | 0 | |
| 2022-06-30 | 35 | $852.7M | 0 | |
| 2022-03-31 | 34 | $1.0B | 0 | |
| 2021-12-31 | 34 | $1.3B | 0 | |
| 2021-09-30 | 33 | $1.6B | 0 | |
| 2021-06-30 | 30 | $1.5B | 33 | |
| 2021-03-31 | 31 | $1.8B | 41 | |
| 2020-12-31 | 26 | $1.6B | 66 | |
| 2020-09-30 | 22 | $1.1B | 39 | |
| 2020-06-30 | 15 | $954.8M | 54 | |
| 2020-03-31 | 11 | $591.3M | 52 | |
| 2019-12-31 | 10 | $670.5M | 68 | |
| 2019-09-30 | 7 | $388.4M | 83 | |
| 2019-06-30 | 5 | $196.9M | 24 | |
| 2019-03-31 | 6 | $250.1M | 58 | |
| 2018-12-31 | 6 | $292.6M | 42 | |
| 2018-09-30 | 6 | $440.6M | 32 | |
| 2018-06-30 | 5 | $319.1M | 61 | |
| 2018-03-31 | 4 | $169.6M | 32 | |
| 2017-12-31 | 3 | $152.4M | 0 |
Bain Capital Life Sciences Investors, LLC's most significant position changes for 2026-03-31: New buy: Centessa Pharmaceuticals-adr (260); New buy: Alkermes plc (ALKS); Sold out: Mersana Therapeutics INC (MRSN); New buy: Disc Medicine INC (IRON); Sold out: Tango Therapeutics INC (TNGX).
| # | Ticker | Issuer | Weight Change | Shares Change | Action |
|---|---|---|---|---|---|
| 1 | SLDB | Solid Biosciences INC | +3% | +23.98% | Add |
| 2 | NAMS | NewAmsterdam Pharma Company N.V. | +1.5% | — | Unchanged |
| 3 | PHVS | Pharvaris N.V. | +0.9% | -4.52% | Trim |
| 4 | CABA | Cabaletta Bio INC | +0.7% | — | Unchanged |
| 5 | CCCC | C4 Therapeutics INC | +0.7% | — | Unchanged |
| 6 | ANNX | Annexon INC | +0.6% | -0.69% | Trim |
| 7 | SVRA | Savara INC | +0.5% | — | Unchanged |
| 8 | XFOR | X4 Pharmaceuticals INC | +0.5% | — | Unchanged |
| 9 | AVIR | Atea Pharmaceuticals INC | +0.5% | -5.03% | Trim |
| 10 | DNTH | Dianthus Therapeutics INC | +0.4% | -51.25% | Trim |
| 11 | KYTX | Kyverna Therapeutics INC | +0.2% | — | Unchanged |
| 12 | ✓ | Newamsterdam Pharma Company | — | — | Unchanged |
| 13 | RPID | Rapid Micro Biosystems Inc-a | -0.1% | — | Unchanged |
| 14 | UPB | Upstream Bio INC | -2.1% | -34.77% | Trim |
| 15 | HTFL | Heartflow INC | -4.9% | -16.07% | Trim |
| 16 | OLMA | Olema Pharmaceuticals INC | -6.2% | -12.17% | Trim |
| 17 | 260 | Centessa Pharmaceuticals-adr | — | NEW | New buy |
| 18 | ALKS | Alkermes plc | — | NEW | New buy |
| 19 | MRSN | Mersana Therapeutics INC | — | EXIT | Sold out |
| 20 | IRON | Disc Medicine INC | — | NEW | New buy |
| 21 | TNGX | Tango Therapeutics INC | — | EXIT | Sold out |
| 22 | XLO | Xilio Therapeutics INC | — | NEW | New buy |
| 23 | ✓ | Xilio Therapeutics INC | — | EXIT | Sold out |
| Period | Filed | Type | EDGAR |
|---|---|---|---|
| 2026-03-31 | 2026-05-15 | 13F-HR | View on EDGAR |
| 2025-12-31 | 2026-02-17 | 13F-HR | View on EDGAR |
| 2025-09-30 | 2025-11-14 | 13F-HR | View on EDGAR |
| 2025-06-30 | 2025-08-14 | 13F-HR | View on EDGAR |
| 2025-03-31 | 2025-05-15 | 13F-HR | View on EDGAR |
| 2024-12-31 | 2025-02-14 | 13F-HR | View on EDGAR |
| 2024-09-30 | 2024-11-14 | 13F-HR | View on EDGAR |
| 2024-06-30 | 2024-08-12 | 13F-HR | View on EDGAR |
| 2024-03-31 | 2024-05-15 | 13F-HR | View on EDGAR |
| 2023-12-31 | 2024-02-13 | 13F-HR | View on EDGAR |
| 2023-09-30 | 2023-11-14 | 13F-HR | View on EDGAR |
| 2023-06-30 | 2023-08-14 | 13F-HR | View on EDGAR |
| 2023-03-31 | 2023-05-15 | 13F-HR | View on EDGAR |
| 2022-12-31 | 2023-02-14 | 13F-HR | View on EDGAR |
| 2022-09-30 | 2022-11-14 | 13F-HR | View on EDGAR |
| 2022-06-30 | 2022-08-15 | 13F-HR | View on EDGAR |
| 2022-03-31 | 2022-05-16 | 13F-HR | View on EDGAR |
| 2021-12-31 | 2022-02-14 | 13F-HR | View on EDGAR |
| 2021-09-30 | 2021-11-15 | 13F-HR | View on EDGAR |
| 2021-06-30 | 2021-08-16 | 13F-HR | View on EDGAR |
| 2021-03-31 | 2021-05-17 | 13F-HR | View on EDGAR |
| 2020-12-31 | 2021-02-16 | 13F-HR | View on EDGAR |
| 2020-09-30 | 2020-11-16 | 13F-HR | View on EDGAR |
| 2020-06-30 | 2020-08-14 | 13F-HR | View on EDGAR |
| 2020-03-31 | 2020-05-15 | 13F-HR | View on EDGAR |
| 2019-12-31 | 2020-02-14 | 13F-HR | View on EDGAR |
| 2019-09-30 | 2019-11-14 | 13F-HR | View on EDGAR |
| 2019-06-30 | 2019-08-14 | 13F-HR | View on EDGAR |
| 2019-03-31 | 2019-05-15 | 13F-HR | View on EDGAR |
| 2018-12-31 | 2019-02-14 | 13F-HR | View on EDGAR |
| 2018-09-30 | 2018-11-14 | 13F-HR | View on EDGAR |
| 2018-06-30 | 2018-08-14 | 13F-HR | View on EDGAR |
| 2018-03-31 | 2018-05-15 | 13F-HR | View on EDGAR |
| 2017-12-31 | 2018-02-14 | 13F-HR | View on EDGAR |
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