I'm not what precisely sure you are asking about the difference between covered calls and short puts.
I just think it's a topic area that should be discussed more, and something I wish was explained to me earlier on.
Covered Calls are often the "gateway drug" to the options world. Usually at this stage, investors believe Covered Calls are low risk with great reward. But you can accomplish the same thing by selling a put at the same strike price. Same profit potential, same loss potential. Only you can choose to have short puts cash secured (fully or partially) vs the use of margin.
Look at TGT as an example, a good aristocrat dividend stock. Trading this am (premarket) at $137.75.
1. Covered call option
I can buy 100 shares of TGT stock ($13,775) and sell one 9/18 option with a 145 strike for $230.
Cost: $13,545 (stock price less the option received)
Max Profit: Stock moves somewhere north of $145, I keep $230 from the option, plus $725 from the stock gains (if it gets called away for $145 less the $137.75 cost), total $955.
Max Loss: Assuming TGT goes to $0, I'll lose the $13,775 I put into the stock, but I keep the $230 from the option, total loss $13,545.
But it is VERY unlikely that TGT will go bankrupt between now and 9/18. And yet we have to tie up $13k in capital on the play, to hope for a 7% max gain.
Or
2. Naked Put option
I can sell a 145 TGT put with a 9/18 date for $11.60. I don't have to buy any stock. If I want it to be cash secured, I have to keep $14,500 in my account to be able to buy the shares (but since I get $1,160 from the option, I only have to start off with $13,340 in my account). Which means I need $205 less in my account than the covered call option.
Max Profit: If the stock moves somewhere north of $145, I keep the $1,160 from the option.
Max Loss: Assuming TGT goes to $0, I'll have to buy back the shares that are worth $0 for $145, for a loss of $14,500. But I keep the $1,160. Making for a loss of $13,340.
Cost: $13,340 (stock price at $145 to keep it cash secured, less what I will receive from the option).
So the naked put allows me to have a greater max profit ($1,160 vs $955), lower max loss ($13,340 vs $13,545), and lower out of pocket cost up front ($13,340 vs $13,545). And it's the same underlying movement of the stock. But since I have less out of pocket, and greater profit, my potential gains are 8.7% (rather than the 7% for the covered call).
Now consider the use of a margin account. To do the covered call on margin requires a $13k loan from your broker, which is very risky, expensive, and in my opinion dumb. So you need $13k in cash to tie up into the investment. But for the naked put, you don't need all $13k tied up in that trade, sitting in cash waiting for TGT to go bankrupt (which isn't likely to happen). All I need is ~$3,800 in cash in my account (roughly 20% of the stock price, plus the option premium) and I can sell the put. And the max profit is the same. But $1,160 gain on $3,800 of cash is a 30% gain (instead of an 8.7% gain).
So, if I had $14,000, I could tie up $4,000 to sit in cash on the naked put (in the event TGT dropped 30% in the next 30 days), and then I could put $10,000 in other investments (bonds, for example). If I gained anything on the other investments, it adds to my profit. And if I chose a diversified investment for my other option, I'm even further reducing my risk. If TGT drops more than 30% in 30 days, I can pull out of my other investments to cover the loss and buy back the stock.
Considering the naked put and the covered call is the same play on the same stock moving in the same direction, it surprises me that the naked put isn't talked about to beginners as often as the covered call. Especially when the profit is slightly higher, and the max loss is slightly less. Considering I wished I knew this earlier, I just figured it would be worthwhile to talk about it here.