I already paid my withholding tax on my 401K, do I still need to fill out a 1099

[KatrinaB]

Yes. You must always file form 1099-R, as it is reported to the IRS. When you file the form, you will get credit for the tax that was already withheld. You may also owe a 10% tax penalty, if you withdrew it before the age of 59 1/2. Please view the IRS link below to see if you qualify for an exception to this 10% penalty.

https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-tax-on-early-distri...