Unfortunately, you were wrong. Margin interest is included in investment expense on 1040 Schedule A. For those who choose standard deduction over itemized deduction, they can't claim margin interest anywhere. --- nord wrote: margin interest 算在你交易成本里,算在cap gain loss里面。 it is what i did. i could be wrong。 http://www.trader1688.com/bb/viewtopic.php?f=20&t=15786&sid=bb4