Are option contracts subject to mark to market rules
If I sell a covered call, on stock I own 100%, there is no risk of a margin call. The stock goes to zero, I'm still not ask to send in more money. But, if bought on margin, margin rules apply.  A naked put would require you to be able to buy the stock if put to you. As the price of the stock drops, you still need to be able to buy it at the put strike price.  Mark to market is just an expression describing how your positions are considered each day.