- Quarter end
- 30 Sep 2025
- the date the book describes
- Filed
- 17 Nov 2025
- latest of these filings; the earliest 13 Nov 2025
- Managers listing it
- 4
- at least, of 95 tracked, among listed positions
- Comparable managers
- 95
- filed both Q2 2025 and Q3 2025; 2 listed it in both
- Shares listed
- 1,685,120
- combined, among listed positions
- Reported value
- $66m
- combined, at the quarter end
Among the 95 comparable managers: 3 buyers (opened or added shares) and 1 seller (trimmed or exited), at least, among listed positions. Their net change in shares is not known from listed positions, because at least one of them lists it in only one of the two quarters.
Managers listing ACMR in Q3 2025
4 of 4 holders
| Action | Filing | |||||
|---|---|---|---|---|---|---|
| Southeastern Asset Management Inc | 1,485,687 | $58m | 2.97% | Added | +299,943 | 14 Nov 2025 (the filing on sec.gov) |
| Dodge & Cox | 122,892 | $4.8m | under 0.1% | Added | +41,800 | 13 Nov 2025 (the filing on sec.gov) |
| Discovery Capital Management LLC | 66,600 | $2.6m | 0.14% | New | new | 14 Nov 2025 (the filing on sec.gov) |
| PDT Partners LLC | 9,941 | $389k | under 0.1% | Trimmed | n.a. | 17 Nov 2025 (the filing on sec.gov) |
Largest increases and reductions, by shares
Increases
- Southeastern Asset Management Incexisting position · 1,485,687 shares now+299,943
- Discovery Capital Management LLCnew position · 66,600 shares now+66,600
- Dodge & Coxexisting position · 122,892 shares now+41,800
Reductions
No reduction among listed positions.
New positions and exits
New (1)
Exited (0)
No exit shown by a manager’s own filing.
Ownership over time
Tracked managers listing it, at least.
| Quarter | Holders | Reported value | Buyers | Sellers |
|---|---|---|---|---|
| Q1 2020 | 1 | $48k | n.a. | n.a. |
| Q3 2020 | 2 | $23m | n.a. | n.a. |
| Q4 2020 | 3 | $36m | n.a. | n.a. |
| Q1 2021 | 2 | $3.4m | n.a. | n.a. |
| Q2 2021 | 1 | $22k | n.a. | n.a. |
| Q3 2021 | 1 | $24k | n.a. | n.a. |
| Q4 2021 | 1 | $19k | n.a. | n.a. |
| Q1 2022 | 1 | $14k | n.a. | n.a. |
| Q2 2022 | 1 | $11k | n.a. | n.a. |
| Q3 2022 | 1 | $8k | n.a. | n.a. |
| Q4 2022 | 3 | $1.6m | n.a. | n.a. |
| Q1 2023 | 2 | $1.2m | n.a. | n.a. |
| Q2 2023 | 1 | $1.0m | n.a. | n.a. |
| Q3 2023 | 2 | $14m | n.a. | n.a. |
| Q4 2023 | 2 | $15m | 0 | 2 |
| Q1 2024 | 1 | $25m | 1 | 0 |
| Q2 2024 | 1 | $20m | 1 | 0 |
| Q3 2024 | 2 | $16m | 1 | 1 |
| Q4 2024 | 3 | $8.4m | 3 | 0 |
| Q1 2025 | 4 | $27m | 3 | 1 |
| Q2 2025 | 2 | $33m | 2 | 1 |
| Q3 2025 | 4 | $66m | 3 | 1 |
| Q4 2025 | 5 | $125m | 12 | 17 |
| Q1 2026 | 3 | $78m | 12 | 13 |
| Q2 2026 | 6 | $411m | 17 | 8 |
Compare with…
Holders over time, buyers and sellers, and the managers holding both, side by side for up to four stocks.
ACMR and GE →ACMR and LRCX →ACMR and GEV →Choose a stock to compare with ACMR →
How much of the picture this is
A 13F is a manager’s long US-listed equity book at a quarter end, filed up to 45 days later. It shows no shorts, cash, bonds or performance, and it is never today’s portfolio. Large books are listed to their largest positions, so a manager missing from this table may still hold a small position below that line. These are 95 tracked managers, not the institutional market.
Which funds own ACMR, latest filings →Back to the 13F Explorer →