Mass General Brigham, Inc
Long book
$468.9M
Q1 2026
Positions
6
Top-10 weight
100%
concentration
Last quarter
+8.0%
SPY +14.8%
Turnover
14%
of book per quarter
Strategy in plain words
auto-generated from filingsMass General Brigham, Inc is a wealth-management firm allocating client money, specialised in industrials (71% of the long book), running a $468.9M US long book across 6 positions.
The portfolio is extremely concentrated — the top 10 positions are almost the whole book. Turnover is modest: positions are typically held for years. Current anchor positions: ISHARES MSCI ACWI ETF, KARMAN HOLDINGS INC, REVOLUTION MEDICINES INC, TANGO THERAPEUTICS INC, MAZE THERAPEUTICS INC.
Over the last 5 quarters its long book ran on average 4.9pp per quarter behind the S&P 500, beating the index in 2 of 5 quarters. Its holdings are mechanical (indexing / client flows), so position changes carry no stock-picking signal.
Implied long-book return vs S&P 500
methodology: positions priced quarterly, no shorts/options Fund long book S&P 500
Q1 2024
-9.5%
Q2 2024
+7.3%
Q3 2024
-7.7%
Q4 2025
+0.4%
Q1 2026
+8.0%
Sector allocation
Industrials 71%
Healthcare 29%
Long book by quarter
What does Mass General own?
Q1 2026 13F| Company | Sector | Shares | Value | % of book | Change |
|---|---|---|---|---|---|
| KRMN KARMAN HOLDINGS INC | Industrials | 1.6M | $125.0M | 26.7% | Held |
| RVMD REVOLUTION MEDICINES INC | Healthcare | 344.1K | $33.5M | 7.1% | Held |
| TNGX TANGO THERAPEUTICS INC | Healthcare | 354.2K | $7.4M | 1.6% | Held |
| MAZE MAZE THERAPEUTICS INC | Healthcare | 240.0K | $7.2M | 1.5% | Held |
| MDLN MEDLINE INC-CL A | Healthcare | 70.4K | $3.1M | 0.7% | +167.6% |