JANA Partners Management portfolio
JANA Partners Management · SEC CIK 1998597
Activist value, sale-of-company minded.
This filing is 94 days old. JANA Partners Management keeps roughly 74% of its positions in a typical quarter, so about 74% of this book is likely still intact today.
How half-life is computedSnapshot half-life is the number of days after the period end at which half of this specific fund's reported book is expected to have changed, measured from its own past filings. It is a decay estimate, not knowledge of current positions.
Largest holdings, as filed
Top 10 of 10 positions. Weights are against the whole filed book. 13F filings cover US-listed holdings only.
| Company | Ticker | Value | % of book | Freshness |
|---|---|---|---|---|
| MERCURY SYS INC | MRCY | $484.29M | 25.5% | |
| COOPER COS INC | COO | $256.90M | 13.5% | |
| STATE STR SPDR S&P 500 ETF T | SPY | $256.12M | 13.5% | |
| LAMB WESTON HLDGS INC | LW | $232.94M | 12.3% | |
| FISERV INC | FISV | $179.63M | 9.4% | |
| MARKEL GROUP INC | MKL | $149.88M | 7.9% | |
| ALKAMI TECHNOLOGY INC | ALKT | $122.27M | 6.4% | |
| SIX FLAGS ENTERTAINMENT CORP | FUN | $87.67M | 4.6% | |
| EVERPURE INC | P | $77.94M | 4.1% | |
| RAPID7 INC | RPD | $54.67M | 2.9% |
Freshness: how likely each position is still held today, from this fund's own turnover history, each position's tenure and the filing's age. Hover a bar for the numbers. Method.
What changed last quarter
Between Q1 2026 and Q2 2026, the largest new position was MRCY, now $484.29M; the largest trim was P (shares down 5%). All of it computed from the two filings, nothing inferred.
Biggest buys, Q2 2026
Exited since Q1 2026
None of the previous quarter's 40 largest positions disappeared from the latest filing.
Exit scan covers the previous quarter's 40 largest positions, a stated bound, because reading a mega fund's entire book per page render is not honest engineering.
Common questions
What are JANA Partners's biggest holdings?
As of the Q2 2026 13F, the largest reported positions at JANA Partners Management are MRCY (25.5% of the book), COO (13.5% of the book), SPY (13.5% of the book).
How big is JANA Partners Management's portfolio?
The latest 13F reports $1.90B across 10 US-listed positions. 13F filings cover US-listed holdings only, so non-US positions and shorts are not included.
Does JANA Partners still hold these positions?
Unknown for certain: a 13F may be filed up to 45 days after quarter end. Based on JANA Partners Management's own filing history, the fund keeps roughly 74% of positions in a typical quarter, so at 94 days since the period end roughly 74% of this book is likely intact. The snapshot half-life for this fund is about 213 days.
What did JANA Partners buy and sell last quarter?
Between Q1 2026 and Q2 2026, the largest new position was MRCY, now $484.29M; the largest trim was P (shares down 5%). All of it computed from the two filings, nothing inferred.
Funds with overlapping books
Every 13F we hold, quarter by quarter
Each filing has its own page: the whole book as filed that quarter and what changed from the filing before.
Inside the app: the full book for JANA Partners Management, quarter on quarter buys and sells, consensus across 140+ funds and copy-to-watchlist.
Source: SEC EDGAR 13F filings. Values are as filed and cover US-listed positions only. A 13F may be filed up to 45 days after the quarter ends, so positions can change before the filing is even public; the freshness figures above quantify that lag instead of hiding it. Educational information, not financial advice.