[0] https://www.cnbc.com/2018/03/20/zuckerbergs-facebook-stock-s...

[1] https://finviz.com/quote.ashx?t=fb (check "insider trading") towards the bottom half of the page

It doesn't take much work

https://www.cnbc.com/2018/03/20/zuckerbergs-facebook-stock-s...

I'm not sure there's any real way to tie this to nefarious intent or insider trading. The timing is so coincidental, however, that it's understandably fueling speculation.