undamentalytics Newsletter
Sign in

Shirley Brian: insider trades

Officer at Micron Technology. No open-market purchases and 22 sales not made under a pre-set plan, reported from January 5, 2010 to July 14, 2017.

What happened after Shirley Brian’s sales?

After their sales, the shares moved +40.2% against the index over 12 months on average (a negative figure means selling was the right call); 41% 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 22 +12.6% +13.6% 27% 5 1.38 0.24 No reliable evidence
Sales, 12 months after the report 22 +40.2% +53.7% 41% 5 0.69 0.53 No reliable evidence
Sales, 12 months after the trade 22 +40.0% +58.5% 41% 6 0.40 0.70 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
Micron Technology MU SVP, DRAM and Emerging Memory022January 5, 2010July 14, 2017

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 14, 2017July 12, 2017 MU Sale $859,465 +23.0%+63.2%+59.7%
May 17, 2017May 15, 2017 MU Sale $1,455,215 +4.6%+77.5%+72.4%
March 30, 2017March 28, 2017 MU Sale $2,523,460 +0.3%+65.6%+66.9%
February 16, 2017February 15, 2017 MU Sale $630,020 +17.3%+74.6%+70.5%
January 10, 2017January 6, 2017 MU Sale $2,001,301 +13.6%+63.9%+83.8%
October 7, 2014October 3, 2014 MU Sale $1,021,800 −1.1%−46.5%−51.3%
July 3, 2014July 2, 2014 MU Sale $2,205,385 +3.3%−52.0%−50.7%
January 15, 2014January 13, 2014 MU Sale $3,478,550 +1.9%+13.9%+18.8%
November 15, 2013November 13, 2013 MU Sale $1,787,940 +29.0%+53.6%+57.4%
November 13, 2013November 11, 2013 MU Sale $4,489,200 +29.1%+53.8%+64.3%
August 15, 2013August 14, 2013 MU Sale $1,490,209 +28.3%+107.3%+91.2%
June 25, 2013June 24, 2013 MU Sale $1,269,832 +13.6%+101.2%+115.1%
May 6, 2013May 3, 2013 MU Sale $48,100 +36.9%+147.1%+158.6%
May 3, 2013May 2, 2013 MU Sale $1,116,350 +39.1%+155.6%+162.2%
April 22, 2013April 19, 2013 MU Sale $1,112,075 +37.0%+157.5%+148.1%
April 26, 2011April 25, 2011 MU Sale $1,070,746 −33.8%−49.5%−47.4%
January 4, 2011January 4, 2011 MU Sale $340,000 +26.4%−18.6%−19.9%
November 16, 2010November 15, 2010 MU Sale $302,269 +52.0%−12.1%−34.5%
July 26, 2010July 23, 2010 MU Sale $336,000 −14.3%−28.7%−28.9%
April 27, 2010April 26, 2010 MU Sale $150,002 −12.8%−0.7%−9.0%
April 5, 2010April 5, 2010 MU Sale $215,592 −5.2%−4.8%−7.7%
January 5, 2010December 31, 2009 MU Sale $215,000 −10.6%−38.3%−39.1%

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