This is on Hacker News why?
Daily stock market quotes are like comments or articles on gossip blogs - it's the opinion of ~0.001% of the market for ~1 second - and the opinion that they give is usually wrong.
Daily stock market quotes are like comments or articles on gossip blogs - it's the opinion of ~0.001% of the market for ~1 second - and the opinion that they give is usually wrong.
This basically causes all calls/puts option contracts on either side to be worthless. It is commonly accepted "fact" (note the quotations) that stock prices are manipulated to some degree on options expiration days to minimize losses of contract writers, who could typically be traders from hedge funds or from some investment bank.
E.g., if you took an at the money (just at 0 intrinsic value) option for a year out, the price might be 20% of the strike price. That 20% will slowly fade over the course of the year. (Or possibly go up, if the volitility of the stock goes way up). If, in 6 months, your stock was in the money a bit, the option would still be worth more than the intrinsic value. (though, dividends can mess with that, and some people excercise options early to catch dividends)
That said, I don't really believe the manipulation story. Perhaps a small amount of market manipulation occurred, but it's not the reason AAPL is in a slump. For that, I think mental state and market sentiment are far far more powerful factors.
Weeklies expire every friday (except on fridays when it is also a monthly expiry - the third friday of every month).
Quarterlies expire the last business day of march, june, september and december.
If, at expiry, the spot is 'x', puts with strikes > x are worthless and calls with strike < x are worthless too. This is true for any x, indepently of HN's belief that x is somewhow magical.