I've never gotten a margin call so I don't know how it works. Do brokerage firms just dump shares as soon as someone's account drops below the minimum or do they wait until the end of the day? In other words could there be a bunch of margin-call sellers late in the day?
Five business days for margin calls to satisfied. Or else broker will dump your shares. So expect AAPL to be sold heavily well into next Wednesday. BTW, if you don't know the margin rules, don't trade on margin.