Hal_Al
Level 15

Get your taxes done using TurboTax

Did the Signing Bonus involve work that's like your main job?

Did the Signing Bonus involve an intent to earn money?

 

You answer yes, both questions.  This is an equivalent to a salary bonus. As such, social security and Medicare tax need to be paid, in addition to income tax.  The way you do that is as "self employment tax", by filing Schedule C and Schedule SE