八字不合 : How much margin is required for that?

约翰の理财库 OP 八字不合 : Strike price x Qty x 100 = Capital / Margin required

Boo Boo Y : Hi John, need to ask you some info on options trade. I'm still in the learning stage.
If  my guess for certain stock is NOT going to rise, let say 10 % by this Friday 18 Oct 24, so on 14 Oct I buy a SELL CALL of that stock of strike price, matured on 18 Oct Friday, which is about 11 % of today's current price. Then on Tuesday 15 Oct, stock price rise to 5% of Monday 14 Oct stock price.
So by buying a BUY CALL of that same strike price, of the same Qty (lot), matured on 18 Oct Friday, is it considered as I'd close the option trade of that SELL CALL ?.. and still gain profit ? i.e. the premium.

约翰の理财库 OP Boo Boo Y : Yes but you’ll only gain the Sell price - Buy price , not the full premium, unless you wait until expiry and collect full premium.
But I must remind you that generally Selling naked call is way risky than selling cash secure put .