HAH. When he said "OVERNIGHT", I do not think he meant you. It was hard to answer in the manner that he asked. REG-T Margin requires a minimum of 25% Maintenance overnight for fully marginable stocks with no house extra requirement. For example holding $100,000 of AAPL would require a minimum of $25,000 of your cash. I think the short requirement is 30% of your cash plus the stock value shorted. PM does not work that way. "Overnight" starts at 8pm est.