When would a stock be called away when selling a covered call, if the underlying asset rises above the call strike price? Would the stock be called away upon expiration only, or as soon as the price of the underlying asset rises above the call's strike price? My idea is to have a fence spread with a covered call, which would pay for the put, with perhaps a slight credit. I would hope for the stock to be called away, so I could build a new fence on a rising market, and gradually accumulate puts. After several iterations, wouldn't I have enough deltas in the accumulated puts to buy fewer and fewer puts to build the fence at the higher level, and therefore achieve the same downside protection with a greater credit? Would this strategy be best suited for longer-term options?