Do SPY options trade until 4:15 PM? If I am short a call that is expiring in the money today, can I wait until 4:10 or 4:12 to buy to cover in order to avoid assignment? And can someone explain to me in plain English: When do VIX options expire? When do VIX options stop trading? When is the underlying index fixed for calcuating the settlement value?
SPY options trade until 415pm et Yes, you can wait to 4:10 to cover to avoid assignment, but your firm may close your position before this time if you don't have the funds to cover assignment. Check with them if they have a deadline. Vix options expire in the AM, although they are not tradeable the morning that they expire. Vix options stop trading at 415pm et, but there is a curb session where they trade for another 45 minutes. Most retail brokers don't offer access to this session, although IBKR does. They will then trade in an overnight session (along with SPX options) starting at 815pm et. The underlying VIX settlement value is based on the opening prices of SPX options 30 days in advance of the expiring options. So, if you had monthly October VIX options, the settlement of the VIX index would be based on the opening prices of November monthly SPX options.
Based on the opening prices on what date? The morning of the expiration date? And what about VIX weekly options? Do they use the options expiring the following week to calculate the settlement value? Is the settlement value posted somewhere on the morning of the expiration date?
All your questions are answered in the link @Overnight posted. Settlement value is posted here an hour or two after the opening Index Settlement Values (cboe.com) The settlement value is based on the opening price of the SPX options the morning of expiration. So, If you have Oct monthly expiring VIX options, it would be based on the opening prices of the November monthly SPX options on the morning of expiration The weeklies settlement price would be based on the SPX weeklies one month in the future. All this information is on the CBOE web site in much greater detail. I have tried to summarize it for you generally.