Join Date: Jul 2015
Posts: 331
Assuming you're in NJ, DE or NV and you are a US citizen, there shouldn't be anything withheld and any W2-G should be already filed and completed since, in my experience, WSOP.com locks up any win that triggers a W2-G until you fill out the paper work.
The amount of your withdraw shouldn't matter (although if it's over $10,000 it will probably trigger a Cash Transaction Report, like any other casino transaction).
I'm not a lawyer or anything. Just speaking based on personal experience.