You missed the key point of my post which is that your purchase at 0.5x will almost certainly be broken by the exchange, so the odds aren't what you naively pretending they are. This ignorance on your part means that…
No, that's irrational. Stock opens at X, you buy at 0.5X, you sell at 0.9X, it goes back to X. Then the exchange breaks the 0.5x trade. Now you still have to deliver the order you sold at 0.9x, but you're buying it at…
You missed the key point of my post which is that your purchase at 0.5x will almost certainly be broken by the exchange, so the odds aren't what you naively pretending they are. This ignorance on your part means that…
No, that's irrational. Stock opens at X, you buy at 0.5X, you sell at 0.9X, it goes back to X. Then the exchange breaks the 0.5x trade. Now you still have to deliver the order you sold at 0.9x, but you're buying it at…