The officer sold the equivalent of about 40,000 shares (by exercising and then reselling long vested stock options) netting about $17.84 per share, pre tax, in cash — but she still holds very substantial amounts of Merck stock (almost $5.5 million worth of it, in fact) — post the transactions, as of October 3, 2016.
This open market NYSE sale was included along with a batch of board of director vestings/tax-surrenders (mostly off-exchange, non open market transactions), so the casual observer might not have noticed it. [And, I am anything but a casual observer. Smile. She also sold in a similar fashion, in early July of 2016.] But these latest two in 2016 are nothing like the size of her July 2014 sales.
Here’s the one most recent SEC Form 4. This is nothing to worry about.
Now you know.