Assignment on American style options can occur any time during the life of the option. However you are unlikely to be assigned early UNLESS the short option has little or no extrinsic value left. Dec options have a fair bit of time value so unless the stock rockets down (causing a mighty drop in your put's extrinsic premium as the option heads deeper itm - iow the extrinsic, aka time value, gets sucked right out of it) you should be ok, just monitor your extrinsic value.Quote from coolguy17:
When I sell a naked put tomorrow on a stock reporting earnings and its in the money expiring in december and what are the chances of me being called out before december?
I'm sorry demoship but this doesn't make any sense. For example, using your formula, what if put strike is 40 and stock price is 47.65 and option bid is 1.20 and there is 25 days to expiry? Thus, with your formula, you get 41.20 which is less than 47.65 but I don't think anyone would likely assign you on an otm put that still has 1.20 extrinsic premium!Quote from demoship:
Here's my way of judging assignment risk:
If (option bid + option strike) <= stock price, there's significant assignment risk.
Quote from coolguy17:
When I sell a naked put tomorrow on a stock reporting earnings and its in the money expiring in december and what are the chances of me being called out before december?
It is a matter of interest carry cost for the market maker. I assume that an ITM Put in Dec has little if any retail involvement. The market maker will buy stock as a hedge when you sell him the Put. If the interest cost (with dividends figured in if appropriate) of carrying the long stock exceeds the current price of the corresponding Call then he will exercise the option. Market makers have different interest levels depending on their size so you have to estimate their cost. If the stock is hard to borrow then things are a little more complicated.Quote from coolguy17:
When I sell a naked put tomorrow on a stock reporting earnings and its in the money expiring in december and what are the chances of me being called out before december?
. An otm put, at expiry, will not be assigned. An itm put at expiry will be automatically assigned. Whether the option is assigned early depends on how much extrinsic value it has left plus there's an element of chance i.e. some buyer wants to exercise his long put early, for whatever reason, and your short put is the one that gets picked out of the hat. The amount of extrinsic value depends on the factors that make up the inputs to the pricing models. If short calls are involved and a dividend is coming up then early exercise is likely when the equivalent strike put has less extrinsic value than the amount of the dividend.