Michael R. Niggli is Director at ESS Tech, Inc. (GWH). They have made 5 open-market trades across 1 company since 2022, most recently 2025-10-13.
CIK 0001377160
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.
5 open-market purchases totalling $188K since 2022, never a sale. Across 5 scored buys the stock is up 0.1% at ninety days, and 4.1 points behind the S&P over the same stretch.
5 scored purchases · one row per filing · discretionary only
| 7d | 30d | 90d | |
|---|---|---|---|
| Accuracy | 40% | 60% | 40% |
| Avg Move | +0.8% | +20.1% | +0.1% |
| Alpha | +1.1% | +15.2% | -4.1% |
| Scored | 5 | 5 | 5 |
| Ticker | Type | Traded | Filed | Price | Value | 7d Stock | 30d Stock | 90d Stock |
|---|---|---|---|---|---|---|---|---|
| GWH | BUY | 2023-05-16 | 2023-05-17 | $0.81 | $8K | +26.6% | +47.9% | +37.2% |
| GWH | BUY | 2023-05-12 | 2023-05-15 | $1.13 | $23K | +23.5% | +59.7% | +48.4% |
| GWH | BUY | 2023-03-06 | 2023-03-07 | $1.65 | $8K | -20.1% | -17.3% | -5.8% |
| GWH | BUY | 2022-12-15 | 2022-12-16 | $2.56 | $49K | -12.7% | -11.9% | -57.7% |
| GWH | BUY | 2022-03-01 | 2022-03-03 | $5.01 | $100K | -13.4% | +22.0% | -21.6% |
Grouped by shared companies and similar filing behaviour. This is a similarity measure, not a ranking or a performance signal.