JANA Partners Management, LP

In its 13F for Q1 2026 (holdings as of March 31, 2026, filed May 15, 2026), JANA Partners Management, LP reported 11 stock positions worth $1.7 billion. Its top holding was Mercury Systems (MRCY) at 18.0% of the portfolio, followed by Cooper Cos (COO, 15.3%) and Fiserv (FISV, 14.8%). Compared with Q4 2025, it opened 1 new position, sold out of 2, added to 3 and reduced 3. The biggest buy was Fiserv (FISV, shares +98%) and the biggest sale an exit from Treehouse Foods (THS).

Most Recent 13F
Q2 2026
Location
NEW YORK, NY
CIK
0001998597
Portfolio Value
$1.7B (Q1 2026)
SEC Filing
0000902664-26-002515 ↗ filed May 15, 2026

Holdings Value

0$500.0M$1.0B$1.5B$2.0B$2.5B Q1 2024: $1.8B Q1 2024 Q2 2024: $1.7B Q2 2024 Q3 2024: $1.8B Q3 2024 Q4 2024: $1.9B Q4 2024 Q1 2025: $1.9B Q1 2025 Q2 2025: $2.0B Q2 2025 Q3 2025: $2.1B Q3 2025 Q4 2025: $1.9B Q4 2025 Q1 2026: $1.7B $1.7B Q1 2026 Q2 2026: $1.9B Q2 2026

Holdings 11 stocks · $1.7B
MRCY Mercury Systems Inc. 17.96% 4,107,424 $299.5M Reduce -17.2%
COO The Cooper Cos Inc. 15.29% 3,565,158 $254.9M Add +1.3%
FISV Fiserv Inc. 14.84% 4,435,605 $247.5M Add +97.5%
SPY SS SPDR S&P 500 ETF Trust-US 13.40% 343,665 $223.5M Reduce -12.2%
LW Lamb Weston Holdings Inc. 12.69% 5,008,635 $211.7M No change
MKL Markel Group Inc. 8.64% 75,307 $144.1M Reduce -7.3%
ALKT Alkami Technology Inc. 5.10% 5,431,388 $85.1M Add +11.0%
FUN Six Flags Entertainment Corp. 4.38% 4,116,099 $73.1M No change
P Everpure Inc. Class A 3.69% 1,042,296 $61.5M New
RPD RAPID7 Inc. 2.23% 6,743,653 $37.2M No change
EHAB Enhabit Inc. 1.77% 2,090,412 $29.5M No change

Portfolio Sells Q4 2025 → Q1 2026
THS Treehouse Foods Inc. Sold out 0.00% −7.15
FRPT Freshpet Inc. Sold out 0.00% −1.77
MRCY Mercury Systems Inc. Reduce -17.2% 17.96% −0.88
SPY SS SPDR S&P 500 ETF Trust-US Reduce -12.2% 13.40% −0.48
MKL Markel Group Inc. Reduce -7.3% 8.64% −0.44

Portfolio Buys Q4 2025 → Q1 2026
FISV Fiserv Inc. Add +97.5% 14.84% +6.99
P Everpure Inc. Class A New 3.69% +3.69
COO The Cooper Cos Inc. Add +1.3% 15.29% +0.28
ALKT Alkami Technology Inc. Add +11.0% 5.10% −0.77

All Filings

QuarterPositions13F Reported ValueTop Holdings
Q2 2026 10$1.9BMRCY, COO, SPY, LW, FISV
Q1 2026Amended 11$1.7BMRCY, COO, FISV, SPY, LW
Q4 2025 12$1.9BMRCY, COO, SPY, LW, MKL
Q3 2025 12$2.1BMRCY, LW, MKL, SPY, COO
Q2 2025 10$2.0BLW, MRCY, SPY, MKL, TRMB
Q1 2025 10$1.9BLW, SPY, MRCY, MKL, TRMB
Q4 2024 10$1.9BLW, TRMB, MRCY, SPY, MKL
Q3 2024 11$1.8BTRMB, SPY, MRCY, LW, THS
Q2 2024 12$1.7BFYBR, SPY, FIS, TRMB, MRCY
Q1 2024 10$1.8BSPY, FIS, TRMB, FYBR, MRCY