What Is a Self-Employment Tax? Definition and Use

Definition

Self-Employment Tax - Self-employment tax is the 15.3% Social Security and Medicare tax owners of pass-through businesses pay on net earnings, covering the employer and employee halves.

The 15.3% rate combines a 12.4% Social Security portion, which applies up to an annual wage base, and a 2.9% Medicare portion with no cap, plus an additional 0.9% Medicare tax on earnings above high-income thresholds. Owners of single-member LLCs taxed as disregarded entities, and actively working members of partnership-taxed LLCs, compute this on Schedule SE and pay it alongside income tax on their personal return each year.

The most common way to reduce it is an S-corp election on Form 2553, which lets an owner-employee take a reasonable salary subject to payroll tax and receive the rest as distributions that avoid self-employment tax. The misconception is that an LLC by itself lowers this tax. It does not: the default LLC owner pays self-employment tax on the full net profit, and only the S-corp election, not the LLC form, changes that math.

A crucial point for non-residents is that self-employment tax applies to US persons with US self-employment income. A non-resident alien with foreign-source income from a US LLC is generally not subject to it, which is a meaningful difference for many international owners of Wyoming, New Mexico, Delaware, and Nevada LLCs and a reason S-corp elections rarely make sense for them.

Self-employment tax is entirely independent of anonymity. Whether an LLC is anonymous or fully public, the owner's self-employment tax is calculated the same way and reported privately to the IRS on the personal return. The privacy of the state formation record has no bearing on how the pass-through profit that flows to the owner is taxed, so tax planning and anonymity are two separate decisions that a founder should make on their own merits rather than assuming one drives the other.