Quote from ChanTrader:
But what happens if you keep the contract size the same and sell the exact same strike price for the next month, even if it is ITM? Assuming the worst case, let's say the put is far ITM, and its value is now $30. The next month's put at the same strike price is $30.10 because it's so far ITM. So by rolling you just avoid paying the piper until the RUT gets back get where it was. You will have a very poor (but still non-zero) gain during the time you are ITM.
Firstly, your margin requirements to sell that same strike put ITM in a further out month is going to more than double from what it was when you first sold it OTM.
If the underlying really tanks, then the margin requirements may go up even more than that.
How much margins are you going to set aside when you first start trading this? I think this is one major problem. If you get a margin call and you can't put up, your position will be liquidated.
By rolling the put, you will lose money from slippage, and commissions. The tiny time premium you make will not even cover that. And because the put is deep ITM, the slipage is going to be much greater than when it was far OTM, because now the bid-ask is going to be of a much higher value. For e.g. when it was far OTM, the bid-ask may be $0.40 - $0.60 (20 cent spread). When it's deep ITM, the bid-ask could be $91.40 - $93.40 ($2 spread).
By the time it takes for that put to get OTM again, you'd have lost a lot of money from slippage, and some from commissions.
In a worst case, the put could get so far ITM that it's no longer listed for trading. Unlikely, but a possibility.
More importantly, is the ROI of this strategy worth trading? If the puts ever get ITM, you're tying up a lot of capital which is not working for you, and there is no telling how long it will be tied up there. And as the underlying tanks more, you're going to need more and more capital to be tied up not working for you. Psychologically it's kinda hard to do that, throwing money after a bad trade.
But other than these points, I could not think of any other way this could not work. But it's an interesting idea.