I have accounts at both Fidelity and Interactive. It appears to me that the margin requirements of the two are very different. Fidelity's are spelled out as the higher of (a)25% of the stock price minus any OTM amount plus the premium or (b) 15% of the strike price plus the premium. Interactive's aren't spelled out, but I used their demo ( the one that has Portfolio Margin -- which I have) AND FOUND THAT THE MARGIN REQUIREMENT AT I'ACTIVE SEEMS TO BE HALF THAT AT FIDELITY? Is this right?