JANA Partners Management, LP
Barry Rosenstein•CIK: 1998597•Filing: Q4 2025
**JANA Partners Management, LP** Managed by Barry Rosenstein, JANA Partners oversees $1.9B in assets across a concentrated portfolio of 12 positions. The fund exhibits significant conviction in its top holdings, notably maintaining a substantial allocation to MRCY at $362.1M and COO at $288.5M. Further diversification is evident through core positions in SPY ($266.9M) and LW ($209.8M). This structure suggests a focused, large-cap tilt with high conviction in select market leaders.
Total AUM
$1.9B
QoQ Performance
-7.0%
Positions
12
Top 10 Concentration
97.2%
Latest Filing
Q4 2025
Top Holdings Allocation
MRCY
COO
SPY
LW
MKL
FISV
THS
ALKT
MRCY18.8%
COO15.0%
SPY13.9%
LW10.9%
MKL9.1%
FISV7.8%
THS7.1%
ALKT5.9%
📈 Biggest Buys
📉 Biggest Sells
Sector Breakdown
Other86.1%
ETF13.9%
🚪 Exited Positionssold since Q3 2025
Changes from Q3 2025
NEW1 new position
↑5 increased
↓4 decreased
Historical Filings
Q1 2026Q4 2025Q3 2025Q2 2025Q1 2025Q4 2024Q3 2024Q2 2024Q1 2024Q4 2023Q3 2023Q2 2023