If your business is organized as a sole proprietorship or as a wholly owned limited liability company (LLC), you’re subject to both income tax and self-employment tax. There may be a way to cut your tax bill by conducting business as an S corporation. Fundamentals of self-employment tax The self-employment tax is imposed on 92.35% of self-employment income at a 12.4% rate for Social Security up to a certain maximum ($142,800 for 2021) and at a 2.9% rate for Medicare. No maximum tax limit applies to the Medicare tax. An additional 0.9% Medicare tax is imposed on income exceeding $250,000 for married couples ($125,000 for married persons filing separately) and $200,000 in all other cases. What if you conduct your business as a partnership in which you’re a...