undamentalytics Newsletter

Harrison Robert Gardner: insider trades

Officer at 2 companies we cover. No open-market purchases and 16 sales not made under a pre-set plan, reported from May 12, 2011 to November 12, 2025.

What happened after Harrison Robert Gardner’s sales?

After their sales, the shares moved −45.7% against the index over 12 months on average (a negative figure means selling was the right call); 90% 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

Harrison Robert Gardner: 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 10 −9.8% −13.0% 70% 4 −1.67 0.19 No reliable evidence
Sales, 12 months after the report 10 −45.7% −51.4% 90% 4 −1.56 0.22 No reliable evidence
Sales, 12 months after the trade 10 −45.9% −50.8% 90% 4 −1.48 0.24 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
Sera Prognostics, Inc. SERA Chief Information Officer011June 6, 2023November 12, 2025
Myriad Genetics Inc MYGN Chief Information Officer05May 12, 2011February 20, 2014

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
November 12, 2025November 10, 2025 SERA Sale $17,103 not yetnot yetnot yet
August 11, 2025August 8, 2025 SERA Sale $15,143 not yetnot yetnot yet
May 9, 2025May 8, 2025 SERA Sale $15,984 not yetnot yetnot yet
March 7, 2025March 6, 2025 SERA Sale $13,524 not yetnot yetnot yet
February 14, 2025February 12, 2025 SERA Sale $33,420 not yetnot yetnot yet
November 12, 2024November 11, 2024 SERA Sale $34,602 −46.6%−68.9%−74.0%
August 8, 2024August 7, 2024 SERA Sale $37,263 −9.0%−91.4%−92.5%
May 10, 2024May 8, 2024 SERA Sale $47,010 −26.9%−88.6%−89.2%
March 7, 2024March 6, 2024 SERA Sale $19,285 −18.7%−65.6%−65.7%
February 7, 2024February 6, 2024 SERA Sale $45,490 +16.2%−73.3%−68.5%
June 6, 2023June 5, 2023 SERA Sale $16,150 not yetnot yetnot yet
February 20, 2014February 20, 2014 MYGN Sale $635,806 −14.3%−23.2%−22.4%
February 12, 2014February 12, 2014 MYGN Sale $421,289 +19.9%−6.6%−7.6%
December 4, 2012November 30, 2012 MYGN Sale $104,226 −19.6%−37.3%−35.8%
February 17, 2012February 15, 2012 MYGN Sale $51,574 +12.9%−6.6%−11.3%
May 12, 2011May 9, 2011 MYGN Sale $461,680 −11.7%+4.6%+8.5%

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 Harrison Robert Gardner traded and do not suggest the use of non-public information. How every insider compares · the insider trading backtest.