S-Corp vs. C-Corp vs. LLC: The Entity Election That Follows You for Years
The entity election is the single most consequential tax decision a business owner makes — and most owners make it the day they form the company, in five minutes, without modeling the numbers. That decision follows them for years, and unwinding it can cost more than it would have to get it right the first time.
S-corp, C-corp, and LLC are not interchangeable. Each one creates a fundamentally different tax situation — different rates, different self-employment tax treatment, different implications for investors, and different problems when you eventually want to sell. The right answer depends on your revenue, your profit margins, your state, whether you plan to raise capital, and what kind of exit you are building toward. It is worth modeling all three before you make the choice, and revisiting the model every few years as your business grows.
Here is what each structure actually does to your tax bill — and when each one wins:
- LLC (default taxation) — maximum flexibility, no self-employment tax arbitrage. A single-member LLC is a disregarded entity by default — all income flows directly to your personal return on Schedule C. A multi-member LLC is a partnership by default, filing Form 1065 with K-1s to partners. Both structures expose 100% of net profit to self-employment tax (15.3% on the first $176,100 in 2026, 2.9% above that). For low-revenue businesses or those in early stages, the simplicity and flexibility are worth it. For profitable businesses, the SE tax exposure is often the argument to elect differently.
- S-corp election — the self-employment tax savings engine, with conditions. An S-corp (either an LLC electing S treatment or a corporation electing S status) taxes only the shareholder-employee's W-2 salary through payroll tax. Distributions above the salary are not subject to SE tax. A business generating $300,000 of profit where the owner takes a $120,000 reasonable salary saves SE tax on the remaining $180,000 — roughly $25,000 in tax savings annually. The IRS requires that the salary be "reasonable compensation" for the work performed; an owner paying themselves $1 to avoid payroll tax invites audit and reclassification. The break-even point where the accounting overhead of S-corp payroll is worth the SE tax savings is generally around $50,000 to $80,000 of net profit, depending on state.
- C-corp — the 21% flat rate is compelling in exactly the right circumstances. Since the Tax Cuts and Jobs Act, C-corps pay a flat 21% federal corporate tax rate on all retained earnings. For businesses that reinvest heavily and distribute little, the 21% rate can be lower than the combined pass-through rate on owner income. For VC-backed companies, C-corp is the only practical structure — most institutional investors will not invest in a pass-through entity because of the K-1 complexity and the inability to issue preferred stock cleanly. For solo operators distributing most of their profit, C-corp creates double taxation — once at the corporate level, again when dividends are paid to shareholders — that usually outweighs the rate benefit.
- The check-the-box election gives LLCs enormous flexibility. An LLC can elect to be taxed as a C-corp, an S-corp, or remain its default treatment, using IRS Form 8832 (for C treatment) or Form 2553 (for S treatment). This flexibility is unique to LLCs — it means you get liability protection as an LLC while accessing whatever tax treatment is most advantageous. The election can be made retroactively in some circumstances. Most tax advisors recommend forming an LLC and then making the appropriate tax election, rather than forming a corporation directly, precisely because of this flexibility.
- Built-in gains (BIG) tax when converting from C to S — a serious trap. If a C-corp converts to S-corp status, any assets that had built-in gains at the time of conversion are subject to the BIG tax if sold within five years. The BIG tax is assessed at the highest corporate rate (21%) on the gain that existed at the conversion date. For asset-heavy businesses — real estate, equipment, IP — this is a material liability that can make the conversion economically unwise. Planning for this window is essential; many owners find out about BIG tax only when they are trying to sell.
- QSBS exclusion (Section 1202) — the most powerful C-corp advantage for startup founders. Qualified Small Business Stock held in a C-corp for more than five years can qualify for a 100% federal capital gains exclusion — up to $10 million per investor, or 10x the investor's basis, whichever is greater. This is a tax-free exit for early investors and founders in qualifying C-corps (generally businesses with less than $50M in assets at time of issuance). QSBS is one of the few reasons to choose C-corp over S-corp for a business that is not raising institutional capital — but the five-year hold and issuance requirements must be met precisely or the exclusion is lost.
- State-level treatment adds a critical layer of complexity. Some states do not recognize the S-corp election at all — California imposes its own 1.5% S-corp franchise tax, and some states tax S-corp income at corporate rates regardless of the federal pass-through treatment. New Hampshire taxes business profits at the entity level even for pass-throughs. Tennessee has a franchise and excise tax structure that can make S-corp elections expensive. An entity election that is optimal for federal purposes can be inefficient in a high-tax state, and vice versa. Any entity analysis that ignores state taxes is incomplete.
- Timing the election — the S-corp late election relief and retroactive filings. The S-corp election deadline is March 15 of the year the election is to take effect (or within two months and 15 days of formation for a new entity). Missing the deadline is not necessarily fatal — the IRS has Revenue Procedure 2013-30, which provides relief for late S-corp elections when the failure was inadvertent and the entity has been treated consistently as an S-corp. Understanding this relief mechanism, and the conditions required to qualify for it, is something every owner operating without an election should know.
What it costs to get the entity election wrong: years of overpaid SE tax on profitable S-corp-eligible income, BIG tax surprises when you eventually want to sell, missed QSBS exclusions worth millions for growth businesses, and a state tax bill that erases what the federal election saved.
We help business owners model the actual after-tax difference between entity structures for their specific revenue level, state, and exit timeline — and we file the elections and restructuring paperwork to get them there.