Stephen Mandel's Lone Pine Capital opened a new position in SEAGATE TECHNOLOGY ULC (STX) in 2026 Q2, according to the 13F-HR filed with the SEC on August 14, 2026. The filing lists 1M shares worth about $965.1M at June 30, 2026, 5.9% of the reported portfolio. STX enters the book as the 3rd largest of 34 stock positions.
What did the 2026 Q2 filing report for STX?
As of June 30, 2026, from the 13F-HR filed August 14, 2026.
| Value | |
|---|---|
| Shares | 1M |
| Reported value | $965.1M |
| Portfolio weight | 5.9% |
| Rank in portfolio | 3rd of 34 |
How big is the new STX position?
Stephen Mandel opened 13 stock positions in 2026 Q2; STX is the 2nd largest of them by weight. An average stock position in the Stephen Mandel portfolio is 3% of the reported value, so the new name comes in above the fund's typical size.
Where does STX sit in the Stephen Mandel portfolio?
STX ranks 3rd of 34 stock positions in the Stephen Mandel portfolio at 5.9%, above the fund's average stock position of 3%. The largest stock position is NBIS at 7.19%. Next come ASML at 6.92% and STX at 5.9%. The three largest stocks together are 20.01% of the book. The STX purchase was the 3rd largest of the quarter's 49 position changes by percent change to portfolio. Across the 2026 Q2 portfolio, Stephen Mandel reported 34 stock positions, with 13 opened and 15 closed. The total portfolio value is about $16.4B, up 30% from the prior quarter.
Has Stephen Mandel held STX before?
Stephen Mandel has not reported STX before in the filings we track. Our data starts with the quarter ended June 30, 2013.
Did other funds buy or sell STX in 2026 Q2?
Among the other tracked funds that had filed for 2026 Q2 as of August 14, 2026, 2 hold STX. Of those, one opened it this quarter. The largest buyer of STX this quarter was Chase Coleman III. The largest seller was Lewis Sanders. Every tracked holder of STX is on the STX ownership page.
FAQ
How many STX shares does Stephen Mandel hold?
Stephen Mandel holds 1M shares of STX as of June 30, 2026, worth about $965.1M.
What is STX's weight in the Stephen Mandel portfolio?
STX is 5.9% of the Stephen Mandel portfolio and ranks 3rd of 34 stocks by weight.
Has Stephen Mandel owned STX before?
No. Stephen Mandel has not reported STX before in the filings we track, which start with the quarter ended June 30, 2013.
How many other tracked funds hold STX?
2 other tracked funds that had filed for 2026 Q2 hold STX. One of them opened it this quarter.