undamentalytics Newsletter
Sign in

Thorson John A: insider trades

Chief financial officer, Officer at Westamerica Bancorporation. No open-market purchases and 31 sales not made under a pre-set plan, reported from January 27, 2010 to April 29, 2025.

What happened after Thorson John A’s sales?

After their sales, the shares moved −11.2% against the index over 12 months on average (a negative figure means selling was the right call); 77% 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

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 31 −2.6% −3.6% 74% 12 −1.31 0.22 No reliable evidence
Sales, 12 months after the report 31 −11.2% −12.1% 77% 12 −3.46 0.005 Strong evidence: seller right
Sales, 12 months after the trade 31 −11.6% −10.6% 77% 12 −3.53 0.005 Strong evidence: seller right

“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
Westamerica Bancorporation WABC SVP/Treasurer031January 27, 2010April 29, 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
April 29, 2025April 28, 2025 WABC Sale $108,943 −14.5%−12.9%−13.5%
April 24, 2024April 22, 2024 WABC Sale $51,964 +10.8%−4.2%−4.9%
October 24, 2019October 23, 2019 WABC Sale $954,822 −8.8%−30.1%−32.8%
January 30, 2019January 28, 2019 WABC Sale $565,512 −5.6%−17.0%−18.7%
May 7, 2018May 4, 2018 WABC Sale $329,217 +1.9%+4.7%+6.1%
May 3, 2018May 2, 2018 WABC Sale $113,600 +2.2%+6.1%+5.0%
April 30, 2018April 27, 2018 WABC Sale $113,240 +1.2%+5.2%+3.9%
January 24, 2018January 23, 2018 WABC Sale $548,944 −2.3%+8.6%+7.5%
October 27, 2017October 26, 2017 WABC Sale $733,118 −6.6%−1.7%−6.3%
April 27, 2017April 25, 2017 WABC Sale $487,422 −4.8%−8.9%−9.4%
April 25, 2017April 24, 2017 WABC Sale $75,691 −8.5%−12.1%−10.2%
February 2, 2017January 30, 2017 WABC Sale $520,005 −7.9%−14.9%−17.8%
January 26, 2017January 24, 2017 WABC Sale $2,955,288 −8.3%−18.4%−13.9%
May 2, 2016April 29, 2016 WABC Sale $68,061 −4.9%+1.5%−1.2%
April 27, 2016April 25, 2016 WABC Sale $1,734,473 −7.4%−1.6%+0.4%
July 24, 2015July 22, 2015 WABC Sale $1,117,550 −8.9%−8.8%−6.4%
April 21, 2015April 17, 2015 WABC Sale $52,756 +15.6%+17.5%+16.3%
May 2, 2014April 30, 2014 WABC Sale $52,225 −8.4%−22.9%−23.6%
January 23, 2014January 22, 2014 WABC Sale $270,000 −5.8%−31.2%−30.3%
October 30, 2013October 28, 2013 WABC Sale $1,231,474 −3.6%−18.1%−21.1%
October 29, 2013October 25, 2013 WABC Sale $1,177,922 −7.5%−20.2%−22.7%
October 22, 2013October 18, 2013 WABC Sale $554,929 −3.5%−22.9%−21.9%
July 19, 2013July 19, 2013 WABC Sale $1,034,856 +6.5%−15.4%−14.1%
May 2, 2013May 1, 2013 WABC Sale $43,746 +7.8%+0.5%+1.5%
April 26, 2012April 25, 2012 WABC Sale $64,423 +1.6%−20.6%−21.8%
August 4, 2011August 3, 2011 WABC Sale $45,814 −2.3%−12.0%−10.6%
July 21, 2011July 21, 2011 WABC Sale $24,455 −2.6%−6.5%−6.7%
February 8, 2011February 4, 2011 WABC Sale $288,558 −0.7%−6.3%−7.9%
April 27, 2010April 23, 2010 WABC Sale $356,370 −0.1%−27.6%−28.5%
April 20, 2010April 16, 2010 WABC Sale $657,082 −2.7%−26.9%−25.4%
January 27, 2010January 25, 2010 WABC Sale $200,948 −3.7%−28.5%−29.3%

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 Thorson John A traded and do not suggest the use of non-public information. How every insider compares · the insider trading backtest.