So here is an example:
1) You own 1000 shares of google @$1,500 (long shares) = $1.5M paid.
2) You write 10 60-day $1,800 OTM calls for a premium of say 2%. Your borrow rate with IB is 1.5% per year, so will eat 0.25%*maintenance margin (let's call that peanuts for now).
3) You sell 10 60-day...