Take a look at TENCENT, China's biggest internet service and e-commerce company.
The stock dropped sharply last month's closing.
(chart from T3B trader, go to "T3B Malaysia US Group" at FB page https://www.facebook.com/groups/798872600209248/)
That was due to China's announcement:-
Then over in US, the following stocks also fell:
and also this
So if we are buying call options on these stocks, gap downs will pull the option premiums down sharply too.
Above is ATVI call option chain of 181116 (or 2018 Nov 16 expiry) c70 (call at strike 70)
This is a 5 day 5 minute chart of the premium.
(you can pull this chart from THINKORSWIM quickchart when you right click the "more info" at the chain)
For EA, the premium also fell last week.
Premium chart of EA, expiry 181116 (2018 Nov 16) c110 (call at strike 110)
