undamentalytics Newsletter

Sk Inc. and related entities: insider trades

10% owner at 2 companies we cover. No open-market purchases and 31 sales not made under a pre-set plan, reported from May 28, 2024 to July 17, 2025. Trades reported separately by several related funds or companies are counted once, under this name.

What happened after Sk Inc. and related entities’s sales?

After their sales, the shares moved −76.8% against the index over 12 months on average (a negative figure means selling was the right call); 100% trailed it.

With 296 insiders tested, some will look skilled or unskilled by chance alone: when we replaced each insider’s stocks with random companies bought on the same days, about 5.7 cleared the bar ahead and 23.3 behind. One record on its own proves little.

Trade by trade

Sk Inc. and related entities: trades against the S&P 500 afterwards
MeasuredTrades countedAverage vs S&P 500MedianWent the right wayYearst-statisticp-valueEvidence
Purchases, 3 months after the report 0 — — — — — — Not enough years
Purchases, 6 months after the report 0 — — — — — — Not enough years
Purchases, 12 months after the report 0 — — — — — — Not enough years
Purchases, 12 months after the trade 0 — — — — — — Not enough years
Sales, 3 months after the report 9 +9.1% +27.4% 33% 1 — — Not enough years
Sales, 12 months after the report 9 −76.8% −76.4% 100% 1 — — Not enough years
Sales, 12 months after the trade 9 −79.4% −77.1% 100% 1 — — Not enough years

“Average vs S&P 500” is the stock’s return including dividends minus the index’s over the same dates, from the close on the first trading day after the report, or from the close on the trade date. Only windows that have finished are counted. For sales, a negative figure means the stock lagged after it was sold, so selling was the right call (green). “Went the right way” is the share of purchases that beat the index, or of sales that trailed it. The t-statistic uses one average per year of reports, because one person’s trades bunch into the same stock and weeks, and needs trades in at least four different years; the p-value comes from the t distribution with that number of years (with four years, a t of 2 has p = 0.14). “Some evidence” means p under 5%, “strong evidence” p under 1% over at least six years.

Companies traded

CompanyTitle on the latest filingPurchasesSalesFirst reportLatest report
SES AI Corp SES —021October 2, 2024December 19, 2024
Net Power Inc. NPWR —010May 28, 2024July 17, 2025

Trades and what followed

Moves are against the S&P 500; green means the trade went the insider’s way.

ReportedTradedCompanyTradeValue3 months after report12 months after report12 months after trade
July 17, 2025July 15, 2025 NPWR Sale $6,525,000 not yetnot yetnot yet
December 19, 2024December 17, 2024 SES Sale $292,055 not yetnot yetnot yet
December 17, 2024December 13, 2024 SES Sale $362,964 not yetnot yetnot yet
December 13, 2024December 11, 2024 SES Sale $180,513 not yetnot yetnot yet
December 11, 2024December 9, 2024 SES Sale $199,254 not yetnot yetnot yet
November 26, 2024November 22, 2024 NPWR Sale $5,499,675 −46.4%−94.3%−93.0%
November 21, 2024November 20, 2024 NPWR Sale $10,511,663 −42.1%−93.0%−94.6%
November 15, 2024November 13, 2024 SES Sale $160,000 not yetnot yetnot yet
November 13, 2024November 11, 2024 SES Sale $61,289 not yetnot yetnot yet
November 12, 2024November 7, 2024 SES Sale $98,254 not yetnot yetnot yet
November 7, 2024November 5, 2024 SES Sale $87,874 not yetnot yetnot yet
November 5, 2024November 1, 2024 SES Sale $156,507 not yetnot yetnot yet
November 1, 2024October 30, 2024 SES Sale $11,880 not yetnot yetnot yet
October 30, 2024October 28, 2024 SES Sale $260,376 not yetnot yetnot yet
October 28, 2024October 24, 2024 SES Sale $325,236 not yetnot yetnot yet
October 24, 2024October 22, 2024 SES Sale $528,154 not yetnot yetnot yet
October 22, 2024October 18, 2024 SES Sale $589,000 not yetnot yetnot yet
October 18, 2024October 16, 2024 SES Sale $364,195 not yetnot yetnot yet
October 18, 2024October 16, 2024 NPWR Sale $5,146,815 +7.3%−76.4%−67.5%
October 16, 2024October 14, 2024 SES Sale $470,588 not yetnot yetnot yet
October 15, 2024October 10, 2024 SES Sale $358,000 not yetnot yetnot yet
October 11, 2024October 9, 2024 NPWR Sale $1,685,867 +31.1%−54.8%−58.6%
October 10, 2024October 8, 2024 SES Sale $44,242 not yetnot yetnot yet
October 8, 2024October 4, 2024 SES Sale $110,457 not yetnot yetnot yet
October 7, 2024October 3, 2024 NPWR Sale $557,658 +42.9%−60.3%−68.7%
October 4, 2024October 2, 2024 SES Sale $146,723 not yetnot yetnot yet
October 2, 2024September 30, 2024 SES Sale $603,812 not yetnot yetnot yet
October 2, 2024September 30, 2024 NPWR Sale $329,356 +57.4%−68.7%−73.5%
September 24, 2024September 20, 2024 NPWR Sale $200,830 +37.2%−73.5%−77.1%
September 19, 2024September 17, 2024 NPWR Sale $6,820,058 +27.4%−77.1%−85.0%
May 28, 2024May 23, 2024 NPWR Sale $25,100,000 −32.8%−93.1%−96.5%

Open-market purchases and sales of at least $10,000 in companies we cover, from SEC Form 4 filings; sales made under a pre-set Rule 10b5-1 plan are not shown. “Not yet” means the window has not finished or the share price was under $5 at entry. These are the shares’ moves after each trade: they say nothing about why Sk Inc. and related entities traded and do not suggest the use of non-public information. How every insider compares · the insider trading backtest.