For tax years beginning in 2018 and beyond, the Tax Cuts and Jobs Act (TCJA) created a flat 21% federal income tax rate for C corporations. Under prior law, C corporations were taxed at rates as high as 35%. The TCJA also reduced individual income tax rates, which apply to sole proprietorships and pass-through entities, including partnerships, S corporations, and, typically, limited liability companies (LLCs). The top rate, however, dropped only slightly, from 39.6% to 37%.

On the surface, that may make choosing C corporation structure seem like a no-brainer, but there are many other considerations involved.

Conventional wisdom

Under prior tax law, conventional wisdom was that most small businesses should be set up as sole proprietorships or pass-through entities to avoid the double taxation of C corporations: C corporations pay entity-level income tax and then shareholders pay tax on dividends — and on capital gains when they sell the stock. For pass-through entities, there is no federal income tax at the entity level.

Although C corporations are still potentially subject to double taxation under the TCJA, their new 21% tax rate helps make up for it. This issue is further complicated, however, by another provision of the TCJA that allows noncorporate owners of pass-through entities to take a deduction equal to as much as 20% of qualified business income (QBI), subject to various limits. But, unless Congress extends it, the break is available only for tax years beginning in 2018 through 2025.

No one-size-fits-all answer applies when deciding how to structure a business. The best choice depends on your business’s unique situation and your situation as an owner. Your tax adviser can help you evaluate your options.