So I have a covered call option set to expire this week that i've kind of been mulling over to close out just in case some wild news comes out that shoots the stock up. Bid is 0 and ask is .05 "Last" is .04. I've seen this before in options where I have to make 5 cent intervals but the last is some odd amount that is most definitely not a 5 cent interval. Is it just my broker? I have Etrade.
Could be that someone bought or sold some option combo where this option was just a leg, therefore part of a trade. In such cases the last price may even be wrong because the actual price is unknown, for example when you trade a spread for $0.10, the price of each leg may be arbitrary.
My guess is the market makers don't have to follow the same rules that we do. I get filled between the bid and ask all the time on stocks whose options are supposed to have at least a nickel spread.
Only some stocks allow trading of options in pennies. For the ones that don't, you can still trade spreads in pennies, so you may be seeing one leg of a spread trade.
While I don't really know, would assume if I sold a 5-lot with the fills of 4 @ 5cents and one at 0, it may show last as 4cents!
If you trade through a platform with payment for order flow, you can get price improvements of a penny or two that won’t get put in the order book but will get reported as a trade.