Incorporator The Journal of U.S. Formation
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Editorial 7 MIN READ

The sole proprietorship, a decade in

Ten years of Schedule C filers watching the shield get cheaper and the tax bill get harder to ignore

The Editors
Staff, Incorporator.org
7 min read Updated
Contents 5 sections
  1. What has not changed, and what has
  2. The 2025 self-employment math
  3. Where the form actually breaks
  4. The shape of the 2025 sole prop
  5. Sources

sole proprietorship in 2025 is still the default form for anyone who invoices a client and cashes the check without filing anything with a state. No formation document, no separate EIN (your Social Security number does the work on Schedule C), no liability shield, and a self-employment tax that indexes up with the wage base whether you like it or not.

Ten years after we first wrote about this form, the mechanics are identical and the context has moved. What follows is the 2025 version, with the numbers that actually matter on a return filed next April.

What has not changed, and what has

The legal picture is the same. An individual running a trade or business without forming a separate entity is a sole proprietor for federal tax purposes. Income and expenses go on Schedule C (Form 1040). The net number drops onto Schedule 1, gets taxed at your ordinary individual rate, and triggers self-employment tax on Schedule SE. There is no business return, no corporate layer, no second taxpayer. IRS Publication 334 still lays this out in the same order it did in 2017, with the year-specific figures swapped.

What has moved is everything around the form. The Section 199A qualified-business-income deduction, enacted at the end of 2017, now carves 20% off qualified pass-through income for filers under the 2025 thresholds of $197,300 for single filers and $394,600 for joint filers (Rev. Proc. 2024-40, inflation adjustments for tax year 2025). The Corporate Transparency Act, passed in 2021 and fought over for four years, never applied to sole proprietorships in the first place because the statute only reaches entities "created by the filing of a document with a secretary of state or similar office" (31 U.S.C. § 5336(a)(11)(A)). FinCEN's March 2025 interim final rule narrowed the rule further, limiting beneficial-ownership reporting to foreign entities registered to do business in the United States. Either way, a sole prop has nothing to file.

The reporting perimeter around sole props has also tightened in small but real ways. Third-party payment platforms now issue Form 1099-K whenever a filer crosses $2,500 in aggregate payments for tax year 2025, a figure the IRS set in Notice 2024-85 as the transition step between the old $20,000-and-200-transactions threshold and the eventual $600 floor in the American Rescue Plan. A sole prop who took payments through Stripe, Square, PayPal, or Venmo's business flow in 2025 is considerably more likely to see a 1099-K than they were five years ago. The underlying tax treatment does not change; the paper trail does.

The 2025 self-employment math

The self-employment tax is still 15.3% on the first slice of net earnings, composed of 12.4% Social Security (OASDI) and 2.9% Medicare. For 2025, the Social Security portion caps out at the Social Security Administration's contribution and benefit base of $176,100, up from $168,600 in 2024. Every dollar of net self-employment earnings above that is still subject to the 2.9% Medicare rate with no ceiling.

The Additional Medicare Tax added by the Affordable Care Act (IRC § 1411, computed on Form 8959 and layered on top of the rate in IRC § 1401) tacks on another 0.9% above $200,000 for single filers, $250,000 for married filing jointly, and $125,000 for married filing separately. Those thresholds are statutory and have never been indexed for inflation, so the number of sole props hitting them rises quietly every year that nominal earnings do.

The base you pay on is 92.35% of net earnings from self-employment. You get a deduction for half the SE tax when computing AGI. Neither of those softens the quarterly-estimates problem: miss the deadlines and IRC § 6654 charges a penalty computed at the federal short-term rate plus three percentage points, which at 2025 rates is not small.

A sole prop netting $100,000 in 2025 owes roughly $14,130 in SE tax before any income tax. A sole prop netting $200,000 pays the full $176,100 × 12.4% on the Social Security side ($21,836.40), plus 2.9% Medicare on 92.35% of $200,000 ($5,356.30), plus a sliver of 0.9% Additional Medicare on earnings above the single-filer threshold. That is before the federal income tax on the same dollars, which for most filers at that level runs in the 24% to 32% marginal range.

Where the form actually breaks

The 2017 piece put the liability break at three triggers: first employee, first serious contract, first lease. A decade of client work has not produced a better list. The sole proprietorship is tolerable when the business is solo, insurable, and contracting with counterparties who do not care whether they are buying from an individual or an LLC. It becomes structurally wrong the moment a third party with real damages is in the picture, because a judgment against the business is a judgment against you personally. There is no veil. There was never one.

The switch to an LLC is the cheap part. Formation fees run from $50 in Kentucky or New Mexico to a few hundred in most states. The single-member LLC is a disregarded entity by default under Treas. Reg. § 301.7701-3, so the tax return does not change; the same Schedule C rides through. What changes is the state-law personality of the business and the corporate-veil argument that becomes available when a client sues.

The S-corp election is the other switch, and it has a different threshold. Electing S status (via Form 2553 and, if needed, the late- election relief procedure in Rev. Proc. 2013-30) lets the owner split take-home between a reasonable W-2 salary and distributions, and the distribution portion escapes the 15.3% self-employment tax. The crossover point where the payroll, bookkeeping, and return-preparation costs are clearly outweighed by the tax savings tends to land somewhere between $60,000 and $80,000 of net earnings, depending on the state and the reasonable-compensation posture. We have written a separate walk-through of the crossover math and a piece on the triggers that actually move people off Schedule C.

The shape of the 2025 sole prop

The filer who should still be a sole proprietor in 2025 is the low- revenue, low-risk, solo operator: a tutor, a weekend consultant, a musician with a steady stream of gigs, a freelance writer with a handful of repeat clients and a professional liability policy. The SE tax bill is the price of the default, and at $40,000 or $50,000 of net earnings the numbers are not bad enough to justify the overhead of a second form.

The filer who should have switched is the one whose business quietly crossed one of the thresholds while they were not looking. Crossed the $60,000 net-earnings line and never looked at an S-corp projection. Hired a subcontractor and never formed the entity that would put a layer between the subcontractor's conduct and the owner's personal accounts. Signed a software contract with an indemnification clause and did not notice. Each of those is the same story: the default form is durable until it is not, and the transition happens after the fact, usually during a deposition or a franchise-tax notice.

The consolation is that the transition itself is cheap, documented, and forgiving. The IRS has published relief procedures for almost every election a small-business owner might miss. The secretaries of state have online portals. The form the reader probably needs to leave is the one they never filed to enter.

Sources

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