Mass General Brigham, Inc

CIK 1678378 · View on SEC EDGAR ↗

Portfolio value: $361.1M
Positions: 6
As of: June 30, 2026

Portfolio value QoQ: -23.0% 13F does not disclose cash

Top 10 holdings weight: 100.00%
Top 25 holdings weight: 100.00%
Positions above 1%: 5
Effective number of positions: 2.6

Based on 13F long-equity holdings only (cash, bonds, shorts not disclosed)

Turnover Q2 2026: 0.0% Est. buys $0 · sells $140,379,597

New positions: 0
Increased: 0
Decreased: 2
Closed: 1

On this page

Sector breakdown How the portfolio splits across market sectors.
Portfolio Every stock this institution reports holding, from its latest 13F.
Top moves The biggest position increases and decreases this quarter.
Exited positions Positions the manager fully sold out of last quarter.

Sector breakdown

Healthcare

22.9%

Industrials

21.6%

Other/Unmapped

55.5%

Full portfolio 6 positions

					Streak
ACWI iShares MSCI ACWI ETF	$197,728,359	54.76%	1,259,657	$-94,982,887	Down ×2
KRMN Karman Holdings Inc. Common Stock	$77,977,736	21.60%	1,562,054	$-47,064,687
RVMD Revolution Medicines, Inc. - Common Stock	$64,441,362	17.85%	344,091	$30,978,512
TNGX Tango Therapeutics, Inc. - Common Stock	$11,072,042	3.07%	354,192	$3,662,345
MAZE Maze Therapeutics, Inc. - Common Stock	$7,161,421	1.98%	239,994	$-2,400
MDLN Medline Inc. - Class A common stock	$2,698,209	0.75%	68,413	$-432,678	Down ×1
No matches

Top movers (QoQ)

Security	Action	Shares Δ	Value Δ
ACWI	Trimmed	-894K	-$95.0M
KRMN	Price move only	+0	-$47.1M
RVMD	Price move only	+0	+$31.0M
TNGX	Price move only	+0	+$3.7M
MDLN	Trimmed	-2K	-$433K
MAZE	Price move only	+0	-$2K

Exited positions

Includes corporate events (mergers, delistings) — not all exits are sells

Closed positions reflect 13F reporting changes; for index managers these are often mechanical (delisting, M&A, index rebalancing), not active decisions.

Security	Quarter	Shares before	Value before	Price since exit
RBRK	March 31, 2026	14,000	$1,070,720	100.9%