Let's say I sell a -90 delta and I want to buy it back at -50 delta. Using IB. Maybe I missed it, but I don't see as an option, pardon the pun.
For that particular case (buy back at -50 delta, why not place the order based on underlying >- Strike? That way you are not subject to broker producing unreliable Greeks! However, placing a market order on an option is generally not best idea as you may get trip to cleaners. I do not have IB, but TOS allows placing a limit order based on offset from MARK (say MARK + 25cents) at the time of the trigger condition, which I have used. Mileage may differ depending on liquidity of the option.
Yea I think the closest thing is to look at the current 50 delta option and then set a sell trigger when it hits that 50 delta option strike price. However, I dont use IB so unsure if they have it, IB does have very attractive margin interest rates tho, Anyone knows if those apply to stock positions being held for years? And is it true they offer 6:1 leverage for long term holds?