Thanks @Scataphagos. Is not being subject to W9 withholdings common or do most traders have to use a W9? I'm assuming I'll need one because I'm not really in any special situation (military or anything).
I'm in the process of signing up with suretrader. They are asking for a W9 (includes social security number) in a sketchy email they sent saying they need more information before they can create my account. Is this a common thing for brokers to ask?
On an aside, they also ask for "references"...