The rise to $20.60 and the unexpected drop to $16.60 surely looks like a well-crafted episode.
I maxed out my margin capacity around $19.15-$19.60 before the drop and I have to endure a huge loss due to the margin call. I guess quite some other retail investors and option players might have similar experience.
I'd toss the "well crafted" phrase. Market sentiment towards IMOS changed and we've had five sloppy days in a row against some records highs in some of the indices. My consolation is IMOS, by virtue of it's weakness, is a smaller % of my portfolio.
Sentiment got worsened. I usually sell fast, but on IMOS I must defer to Mr. Caff. I am assured that he is not selling. I will not sell. The snap back in Taiwan was remarkable. We will get a snap back too when the wall of worry looks highest.
Unfortunately you are not alone - my July options expired worthless for a large loss. This drop looked manipulated to some extent. My core holding is still very profitable at an average cost of $12.50 but I did add Aug & Sept options last week and will probably regret it unless I sell well before expiration.
I feel sorry for your loss. As many suggested that timing this one is hard. I prefer as Caff. said, buy on dip and hold. If you play option, sell put as HAS suggested. High return also come with high risk, no exception.