"The IRS Publication 15-B or the Employer's Tax Guide to Fringe Benefits" is a document published by the Internal Revenue Service. The IRS Publication 15-B provides employers with guidance on how to account for fringe benefits when filing tax documents.

Publication 15-B supplements Publication 15 (Circular E), Employer's Tax Guide, and Publication 15-A, Employer's Supplemental Tax Guide. It contains information for employers on the employment tax treatment of fringe benefits.

Publication 15-A contains specialized and detailed employment tax information supplementing the basic information provided in Publication 15.

The federal tax withholding rate on supplemental wages (e.g., bonus payments) exceeding $1 million during a calendar year remains at 37%. The rate for supplemental wages up to $1 million subject to a flat rate remains unchanged from 2022, at 22%.

IRC section 15 provides rules for calculation of a taxpayer's tax liability if a tax rate is changed during a taxpayer's tax year, other than on the first day of that year. The section applies to repeals of tax but not to inflation adjustments.

Personal use of a company vehicle is considered a noncash fringe benefit, so the value of the vehicle usage for personal reasons must be included in the employee's income, and tax must be withheld.

We call this annual limit the contribution and benefit base. This amount is also commonly referred to as the taxable maximum. For earnings in 2023, this base is $160,200. The OASDI tax rate for wages paid in 2023 is set by statute at 6.2 percent for employees and employers, each.