Dennis Thomas St is Director at FORMFACTOR INC (FORM). They have made 64 open-market trades across 4 companies since 2007, most recently 2026-06-16.
CIK 0001339595
Unrated. We grade insiders only on stock they chose to buy on the open market. Grants, option exercises and vesting say nothing about timing, so they don't count — which is why someone can file often and still have no grade. It isn't a bad sign: unrated buys beat every graded tier below A.
2 open-market purchases totalling $88K since 2014, against 62 sales. Too few scored purchases to measure a record yet.
| Ticker | Shares | Value |
|---|---|---|
| AMAT | 267,938 | $109.7M |
| FORM | 28,333 | $3.0M |
| VECO | 61,697 | $2.6M |
| ACLS | 17,695 | $1.9M |
| MTSN | 7,375 | — |
| Total | $117.2M |
Shares reported on the most recent Form 4, priced at the 2026-06-16 close. 1 holding could not be priced and is excluded from the total.
Counted per filing, not per execution lot — a purchase filled in several tranches is one decision.
| Ticker | Type | Traded | Filed | Price | Value | 7d Stock | 30d Stock | 90d Stock |
|---|---|---|---|---|---|---|---|---|
| FORM | SELL | 2026-06-15 | 2026-06-16 | $151.49 | $424K | -0.9% | -26.4% | -29.2% |
| ACLS | SELL | 2026-05-22 | 2026-05-26 | $155.37 | $140K | -11.4% | +8.6% | -25.7% |
| FORM | SELL | 2026-05-19 | 2026-05-21 | $115.84 | $116K | -2.1% | +21.6% | -10.8% |
| VECO | SELL | 2026-05-11 | 2026-05-13 | $61.93 | $87K | +3.7% | +28.7% | -16.8% |
| FORM | SELL | 2026-02-10 | 2026-02-11 | $93.84 | $697K | +4.8% | -6.3% | +37.7% |
| FORM | SELL | 2025-11-17 | 2025-11-17 | $49.85 | $100K | +8.4% | +6.0% | +87.9% |
| FORM | SELL | 2025-05-29 | 2025-05-30 | $31.24 | $94K | +17.6% | +15.3% | -1.0% |
| FORM | SELL | 2024-11-05 | 2024-11-06 | $39.11 | $121K | -10.7% | +0.0% | -6.3% |
| VECO | SELL | 2024-05-13 | 2024-05-14 | $37.72 | $151K | +5.1% | +17.8% | -6.9% |
| FORM | SELL | 2024-05-10 | 2024-05-13 | $56.30 | $113K | +6.2% | +3.8% | -20.5% |
| VECO | SELL | 2023-11-30 | 2023-12-01 | $28.52 | $400K | +5.1% | +8.0% | +28.0% |
| FORM | SELL | 2023-11-14 | 2023-11-15 | $38.24 | $290K | -3.7% | +4.2% | +4.2% |
| FORM | SELL | 2023-02-16 | 2023-02-17 | $32.31 | $840K | -1.6% | -3.2% | -0.3% |
| ACLS | SELL | 2023-02-13 | 2023-02-13 | $127.02 | $1.5M | -2.4% | -2.1% | +1.2% |
| ACLS | SELL | 2022-11-18 | 2022-11-18 | $76.66 | $230K | +5.4% | +4.6% | +69.4% |
| VECO | BUY | 2022-05-16 | 2022-05-17 | $21.60 | $54K | -1.2% | -14.3% | +5.0% |
| ACLS | SELL | 2022-02-10 | 2022-02-10 | $72.81 | $218K | -10.5% | -17.0% | -25.6% |
| FORM | SELL | 2022-02-08 | 2022-02-09 | $41.63 | $500K | -1.9% | -4.6% | -7.7% |
| ACLS | SELL | 2021-08-30 | 2021-08-30 | $50.32 | $176K | -4.3% | -8.2% | +22.3% |
| ACLS | SELL | 2020-05-11 | 2020-05-11 | $26.61 | $160K | -8.8% | +2.6% | -3.9% |
| FORM | SELL | 2020-05-11 | 2020-05-12 | $24.78 | $149K | +1.9% | +4.9% | +17.6% |
| FORM | SELL | 2020-02-10 | 2020-02-12 | $25.94 | $259K | -14.8% | -25.7% | -11.1% |
| ACLS | SELL | 2020-02-10 | 2020-02-10 | $28.27 | $240K | -8.0% | -25.6% | -5.0% |
| FORM | SELL | 2019-11-20 | 2019-11-22 | $22.68 | $113K | +0.9% | +15.1% | +12.0% |
| FORM | SELL | 2019-08-20 | 2019-08-21 | $17.26 | $104K | -0.5% | +12.1% | +33.6% |
Grouped by shared companies and similar filing behaviour. This is a similarity measure, not a ranking or a performance signal.