That is what I thought, but not accurate. With Fidelity, if you sell naked Puts with $25,000 in income, you need $50,000-$100,000 to cover it. If the stock drops like just happened, and that Put is now worth $50,000, you suddenly need $100,000-150,000 in your account. I ended up requiring well over 7 figures to cover my Puts at the same time as my account was dropping 50% in value, forcing me to sell some stock and buy back some of the Puts at 100% loss. A painful lesson. I will still sell them in the future, but far fewer so that I don't get a margin call if the stock drops 50% on me again.
Original poster said that if you sell
one put, at $250, you need $25000 to cover. This is worst case scenario, put being executed, stock going to 0. But one put would net you few hundred bucks, maybe a grand or two, depends on strike/time.
To get 25K income as you said you did, you need to sell lots of puts, and margin requirement should bear little relevance to how much money you raised, it's a percentage of strike price, i.e. money you'd need to spend to have all puts execute against you. If you thought put price x 2 is safe, oh my, I'm sorry about it.
One way to think about it is that brokerage wants to make sure you have enough liquidity to weather 30, 40, 50 or 60% in equity price, and that they wouldn't be on the hook for any of it if you got cleaned. And relevant to that, remember TT007? When brokerage gets nervous, they can cash you in even if you don't have formal margin call yet. There is a whole risk-assessment department whose job is to 'adjust' risky positions that may lead to the loss for the brokerage,
and they are merciless. They sold couple of my innocent, in the money, profitable calls, at the worst possible price, while I was looking to sell them, just because there wouldn't have been enough money in the account to execute them. They did it at 11am on the day of expiration, even-though I had hours to deal with them... Unfortunately, contract allows them to do stuff like this...