Quote from stevegee58:
The margin required for selling naked options is generally the same as buying the underlying. So theoretically one could do this without a margin account at all as long as you have enough cash to cover the max loss.
e.g. You sell a put on 1 $70 put for 0.60 on QQQ @72.58. The max risk is when QQQ falls to 0 after you've been assigned at 70 = 70 - 0.60 = 69.40 = $6,940.
Not exactly, though it's probably better to treat it this way if you don't know what you are doing. In fact, probably best not to sell puts in general if you don't know what you are doing.
The initial margin requirements at OH are:
Long stock (>$3): 50%
Short put: 20% of the underlying stock price minus any out-of-the-money amount plus option premium, OR 10% of the strike price plus option premium, whichever is greater.