undamentalytics Newsletter

Leatherberry William J: insider trades

Officer at 2 companies we cover. 7 open-market purchases and 21 sales not made under a pre-set plan, reported from September 13, 2010 to May 30, 2025.

Would copying Leatherberry William J’s purchases have beaten the S&P 500?

Too few purchases to judge. Only 7 purchases have 12 months of prices after the report; we judge insiders once they have 20. The figures below can swing a long way on a handful of trades. Buying each purchase the day after it was reported, an equal amount each, and holding it 12 months or until they reported a sale would have turned $10,000 on March 5, 2015 into $27,969 by November 2, 2026, +9.2% a year. The copy held shares only 27% of the time, so the fair comparison is the S&P 500 on those same days with Treasury bills otherwise: $17,195, +4.8% a year (the S&P 500 held throughout made $43,624, +13.5% a year). Beta against the index was 0.14. Twelve months after each report, the average purchase was +48.0% against the S&P 500 (median +59.2%), and 86% beat it. Measured from the trade date, the insider’s own timing, the average was +50.5%. After their sales, the shares moved −23.4% against the index over 12 months on average (a negative figure means selling was the right call); 86% 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.

$0$20.0k$40.0k 201520172019202120232025 $43.6k$28.0k$17.2k
Copying Leatherberry William JS&P 500, same days investedS&P 500, held throughout $10,000 copying Leatherberry William J’s open-market purchases from March 5, 2015, before costs and taxes, marked weekly. Each purchase gets the same starting stake, bought at the close of the first trading day after the report and sold 12 months later or the day after a reported sale of that stock; uninvested money earns the Treasury bill rate. “Same days invested” holds the S&P 500 only on the days the copy held shares, Treasury bills otherwise.
Return a year, copying
+9.2%
S&P 500, same days invested
+4.8% (held throughout +13.5%)
Time in shares
27%
Sharpe ratio (S&P 500)
0.43 (0.68)
Biggest drop (S&P 500)
−50% (−34%)
Market sensitivity (beta)
0.14
Purchases copied
7

Trade by trade

Leatherberry William J: trades against the S&P 500 afterwards
MeasuredTrades countedAverage vs S&P 500MedianWent the right wayYearst-statisticp-valueEvidence
Purchases, 3 months after the report 7 +7.5% +5.5% 71% 3 — — Not enough years
Purchases, 6 months after the report 7 +27.7% +33.1% 71% 3 — — Not enough years
Purchases, 12 months after the report 7 +48.0% +59.2% 86% 3 — — Not enough years
Purchases, 12 months after the trade 7 +50.5% +68.0% 86% 3 — — Not enough years
Sales, 3 months after the report 21 −3.9% −7.4% 71% 7 −0.07 0.95 No reliable evidence
Sales, 12 months after the report 21 −23.4% −30.3% 86% 7 −1.77 0.13 No reliable evidence
Sales, 12 months after the trade 21 −24.1% −28.6% 86% 7 −2.00 0.093 No reliable evidence

“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
NMI Holdings, Inc. NMIH Chief Admin. Officer & GC720March 4, 2015May 30, 2025
Century Aluminum Co CENX EVP, Gen. Counsel & Secretary01September 13, 2010September 13, 2010

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
May 30, 2025May 30, 2025 NMIH Sale $718,860 −9.4%−39.3%−40.6%
May 2, 2025April 30, 2025 NMIH Sale $865,200 −10.8%−29.7%−28.6%
August 27, 2024August 26, 2024 NMIH Sale $200,210 −8.7%−18.9%−18.7%
August 2, 2024July 31, 2024 NMIH Sale $980,841 −9.3%−18.3%−20.5%
May 7, 2021May 5, 2021 NMIH Sale $126,250 −11.4%−21.0%−27.0%
March 17, 2021March 15, 2021 NMIH Sale $133,356 −10.7%−30.3%−22.0%
March 11, 2021March 10, 2021 NMIH Sale $260,818 −7.4%−23.4%−24.1%
December 11, 2020December 10, 2020 NMIH Sale $471,858 −0.8%−39.6%−46.4%
November 27, 2020November 24, 2020 NMIH Sale $182,542 +3.4%−38.1%−39.4%
November 20, 2020November 18, 2020 NMIH Sale $90,274 −6.6%−37.4%−43.2%
November 12, 2020November 9, 2020 NMIH Sale $392,186 −10.1%−37.9%−38.5%
December 18, 2019December 16, 2019 NMIH Sale $208,173 −42.7%−50.1%−46.4%
November 26, 2019November 25, 2019 NMIH Sale $257,002 −26.1%−50.6%−47.9%
November 12, 2019November 7, 2019 NMIH Sale $1,861,016 −23.5%−51.5%−47.0%
September 25, 2019September 23, 2019 NMIH Sale $406,638 +10.1%−51.6%−51.2%
March 20, 2019March 19, 2019 NMIH Sale $409,833 +12.4%−39.3%−33.7%
March 14, 2019March 12, 2019 NMIH Sale $1,036,524 +9.3%−20.5%−20.2%
August 28, 2018August 24, 2018 NMIH Sale $556,500 −2.3%+29.8%+23.0%
August 16, 2018August 14, 2018 NMIH Sale $980,974 −0.8%+22.0%+21.9%
June 25, 2018June 22, 2018 NMIH Sale $269,800 +35.1%+63.7%+54.2%
August 31, 2017August 29, 2017 NMIH Purchase $53,250 +50.1%+83.2%+77.3%
June 17, 2016June 16, 2016 NMIH Purchase $37,380 +36.7%+71.4%+80.8%
May 11, 2016May 11, 2016 NMIH Purchase $59,200 +5.5%+59.2%+68.0%
March 16, 2016March 16, 2016 NMIH Purchase $50,600 +3.2%+109.0%+112.2%
December 9, 2015December 7, 2015 NMIH Purchase $69,700 −26.7%+32.1%+26.7%
November 13, 2015November 13, 2015 NMIH Purchase $26,644 −22.9%+8.4%+14.5%
March 4, 2015March 4, 2015 NMIH Purchase $147,800 +6.5%−27.1%−25.7%
September 13, 2010September 10, 2010 CENX Sale $36,238 +29.2%−8.9%−9.4%

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 Leatherberry William J traded and do not suggest the use of non-public information. How every insider compares · the insider trading backtest.