Ding Wei: insider trades

Officer at A. O. Smith. No open-market purchases and 11 sales not made under a pre-set plan, reported from February 11, 2013 to February 20, 2018.

What happened after Ding Wei’s sales?

After their sales, the shares moved +10.9% against the index over 12 months on average (a negative figure means selling was the right call); 18% 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

Ding Wei: trades against the S&P 500 afterwards
Measured	Trades counted	Average vs S&P 500	Median	Went the right way	Years	t-statistic	p-value	Evidence
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	11	+2.8%	+4.2%	46%	6	0.88	0.42	No reliable evidence
Sales, 12 months after the report	11	+10.9%	+15.7%	18%	6	1.12	0.31	No reliable evidence
Sales, 12 months after the trade	10	+10.2%	+16.1%	20%	6	1.15	0.30	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

Company	Title on the latest filing	Purchases	Sales	First report	Latest report
A. O. Smith AOS	President - A. O. Smith China	0	11	February 11, 2013	February 20, 2018

Trades and what followed

Moves are against the S&P 500; green means the trade went the insider’s way.

Reported	Traded	Company	Trade	Value	3 months after report	12 months after report	12 months after trade
February 20, 2018	February 20, 2018	AOS	Sale	$768,659	−3.7%	−22.7%	−22.5%
February 28, 2017	February 27, 2017	AOS	Sale	$1,093,744	+6.6%	+8.9%	+11.2%
May 3, 2016	May 2, 2016	AOS	Sale	$639,539	+16.0%	+25.7%	+19.8%
February 16, 2016	December 12, 2016	AOS	Sale	$37,901	+7.8%	+20.2%	not yet
December 11, 2015	December 11, 2015	AOS	Sale	$106,672	−5.7%	+15.7%	+18.9%
March 5, 2015	March 5, 2015	AOS	Sale	$521,370	+12.2%	+18.4%	+21.0%
February 18, 2015	February 18, 2015	AOS	Sale	$37,613	+9.7%	+17.4%	+17.5%
March 3, 2014	March 3, 2014	AOS	Sale	$124,294	−4.0%	+15.5%	+14.6%
February 11, 2014	February 10, 2014	AOS	Sale	$19,903	−5.6%	+15.0%	+17.5%
October 25, 2013	October 24, 2013	AOS	Sale	$284,811	−6.6%	−9.6%	−11.3%
February 11, 2013	February 11, 2013	AOS	Sale	$18,096	+4.2%	+15.7%	+14.7%

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