undamentalytics Newsletter

8 Rivers Capital, LLC and related entities: insider trades

10% owner at Net Power Inc. No open-market purchases and 14 sales not made under a pre-set plan, reported from September 6, 2024 to September 10, 2026. Trades reported separately by several related funds or companies are counted once, under this name.

What happened after 8 Rivers Capital, LLC and related entities’s sales?

After their sales, the shares moved −88.9% 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

8 Rivers Capital, LLC 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 3 +38.3% +32.9% 0% 1 — — Not enough years
Sales, 12 months after the report 3 −88.9% −88.6% 100% 1 — — Not enough years
Sales, 12 months after the trade 3 −91.6% −92.9% 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
Net Power Inc. NPWR —014September 6, 2024September 10, 2026

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
September 10, 2026September 8, 2026 NPWR Sale $470,000 not yetnot yetnot yet
August 14, 2026August 12, 2026 NPWR Sale $1,394,345 not yetnot yetnot yet
August 6, 2026August 4, 2026 NPWR Sale $530,975 not yetnot yetnot yet
July 23, 2026July 21, 2026 NPWR Sale $319,204 not yetnot yetnot yet
February 23, 2026February 19, 2026 NPWR Sale $396,440 not yetnot yetnot yet
February 2, 2026January 29, 2026 NPWR Sale $128,733 not yetnot yetnot yet
January 16, 2026January 14, 2026 NPWR Sale $1,321,750 not yetnot yetnot yet
December 23, 2025December 19, 2025 NPWR Sale $742,100 not yetnot yetnot yet
December 8, 2025December 4, 2025 NPWR Sale $890,050 not yetnot yetnot yet
November 19, 2025November 17, 2025 NPWR Sale $1,594,115 not yetnot yetnot yet
November 4, 2025October 31, 2025 NPWR Sale $107,278 not yetnot yetnot yet
September 16, 2024September 12, 2024 NPWR Sale $285,637 +32.9%−85.0%−88.6%
September 11, 2024September 9, 2024 NPWR Sale $612,369 +49.9%−88.6%−93.3%
September 6, 2024September 4, 2024 NPWR Sale $2,476,050 +32.0%−93.3%−92.9%

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 8 Rivers Capital, LLC and related entities traded and do not suggest the use of non-public information. How every insider compares · the insider trading backtest.