What U.S. tax code provision allows an individual to write off (non-primary-mortgage) loan interest?

Can't you write off capital losses? I've been able to deduct margin interest from my capital gains.

	▲	valleyer 2 hours ago \| parent [-]
		Margin interest is tax-deductible, but only when you're using the loan to buy more securities. So, in context, a CEO who "works for no salary" and just takes out loans secured by their stock holdings to fund their lifestyle does not get to write off that interest. Not to say the "no salary" thing isn't silly anyway, of course.