4137x Apr 2026

: Unreported income is not credited to your Social Security history, potentially lowering your future monthly benefit payments .

: If you received $20 or more in cash and charge tips in any calendar month and did not report the full amount to your employer .

: Tips under $20 in a month don't need to be reported to your employer, but they still must be included as income on your Form 1040 . Filing Mechanics

IRS is the tax document used to calculate and report the Social Security and Medicare taxes owed on unreported tip income . This includes cash tips, noncash tips, and "allocated tips" shown in Box 8 of your Form W-2 that were not previously reported to your employer . Core Purpose of Form 4137

: It determines the employee's share of FICA (Social Security and Medicare) taxes on tips that weren't taxed during the year .