Yes, a professional corporation can be an S corporation. The IRS applies the same eligibility rules to a professional corporation that it applies to any other domestic corporation, so a firm of physicians, attorneys, accountants, or other licensed professionals can file Form 2553 and elect pass-through treatment. The wrinkle is that state licensing law restricts who can hold shares in a professional corporation, and that restriction shapes how the S election gets made, maintained, and occasionally lost.
Federal Eligibility Rules the Corporation Must Meet
Under Internal Revenue Code Section 1361, an S corporation must be a domestic corporation with no more than 100 shareholders and only one class of stock.1Office of the Law Revision Counsel. 26 USC 1361 – S Corporation Defined Financial institutions and insurance companies are ineligible; professional corporations are not on that excluded list.
The one-class-of-stock rule catches people off guard. Every share must carry identical rights to distributions and liquidation proceeds. Differences in voting rights alone are fine, so senior partners can hold shares with greater voting weight without disturbing the election. What breaks the rule is issuing shares that entitle some owners to a larger cut of profits than others.
Shareholders must be individuals who are U.S. citizens or resident aliens. Partnerships and other corporations cannot own shares. Certain trusts and estates can, including Qualified Subchapter S Trusts and Electing Small Business Trusts, which come up often when professionals do estate planning around their ownership interests.2Internal Revenue Service. S Corporations
An S corporation generally has to use a calendar year. A professional corporation that had been using a fiscal year as a C corp will switch to December 31 upon making the election unless it files a Section 444 election or shows a valid business purpose.3eCFR. 26 CFR 1.1378-1 – Taxable Year of S Corporation Most professional S corps just adopt the calendar year and move on.
Licensing Rules That Limit Who Can Own Shares
This is where professional corporations look different from ordinary ones. In most states, every shareholder of a professional corporation has to hold a valid license in the profession the entity practices. A law firm organized as a professional corporation generally cannot sell shares to an unlicensed investor. An accounting firm cannot bring on a shareholder who isn’t a CPA. The details vary by state, but the principle is the same across jurisdictions: non-professionals cannot control the delivery of professional services.
The 100-shareholder cap rarely bites for a professional firm. The licensing requirement is the harder one to manage. If a shareholder retires, lets a license lapse, dies, or gets disbarred, state law usually gives the corporation a set window — commonly anywhere from 30 days to several months — to buy back or transfer those shares. Court-supervised valuation is available if the parties can’t agree on a price. Missing that window can put both the entity’s standing under state law and its S corp status with the IRS at risk.
Because of this, a professional S corporation should have a buy-sell agreement that covers license loss, death, disability, and retirement, with a valuation method and payment terms set in advance. The point is to avoid negotiating those terms during a crisis.
How to Make the Election on Form 2553
The election is made on IRS Form 2553, “Election by a Small Business Corporation.” The form asks for the corporation’s exact legal name as registered with the state, its Employer Identification Number, date of incorporation, and state of incorporation. Every shareholder has to be listed with name, address, Social Security number, ownership percentage, and signature. All shareholders must consent; there is no majority-rules shortcut.2Internal Revenue Service. S Corporations
For the election to take effect in the current tax year, Form 2553 has to reach the IRS no later than two months and 15 days after the start of that year.4Internal Revenue Service. Instructions for Form 2553 For a calendar-year corporation, that’s March 15. A form filed after the deadline generally takes effect the following year.
The IRS accepts the form by mail or fax. Corporations with their principal office in the eastern half of the country file with the Kansas City, MO 64999 service center (fax: 855-887-7734). Those in the western half file with Ogden, UT 84201 (fax: 855-214-7520).5Internal Revenue Service. Where to File Your Taxes for Form 2553 After processing, the IRS mails a CP261 notice confirming acceptance. Keep that notice permanently; it is the proof of S corp status.6Internal Revenue Service. Understanding Your CP261 Notice
What Happens If the Deadline Was Missed
A late filing is not automatically fatal. Revenue Procedure 2013-30 offers a streamlined path to relief when the corporation intended to be an S corp from the start and the only issue was a late Form 2553. The request has to be made within three years and 75 days after the intended effective date, the corporation needs reasonable cause for the delay, and it must have acted promptly once the mistake surfaced.7Internal Revenue Service. Revenue Procedure 2013-30
To use the relief, file a completed Form 2553 with “FILED PURSUANT TO REV. PROC. 2013-30” written across the top. Include a signed explanation of why the form was late and how the corporation corrected course. Every person who was a shareholder between the intended effective date and the filing date must sign and confirm they reported income consistently with S corp treatment on their personal returns. The form can be attached to a current-year Form 1120-S, filed with delinquent prior-year returns, or submitted on its own.
If the corporation doesn’t qualify under Revenue Procedure 2013-30, the fallback is a private letter ruling from the IRS National Office under Section 1362(f), which takes more time and costs more.8Internal Revenue Service. Late Election Relief
Why Professionals Elect S Corp Status
For most professionals, the reason to make the election isn’t avoiding C corp double taxation. It’s cutting the self-employment tax bill. A sole proprietor pays the 15.3% self-employment tax (Social Security and Medicare) on all net earnings. An S corp shareholder-employee pays payroll taxes only on salary; profits distributed beyond the salary are not subject to those employment taxes.
The catch is the reasonable compensation rule. The IRS requires shareholder-employees who perform more than minor services to pay themselves a reasonable salary before taking distributions. Distributions, personal use of company funds, and so-called “loans” will be recharacterized as wages when the salary is too low.9Internal Revenue Service. S Corporation Employees, Shareholders and Corporate Officers A doctor pulling $400,000 out of a practice cannot pay herself $30,000 and treat the rest as distributions. The salary has to reflect what someone in the role would earn on the open market.
Within those limits, the savings are real. For a professional netting $150,000 from the practice, a reasonable salary in the $50,000 to $80,000 range with the balance distributed can save several thousand dollars a year in employment taxes compared to Schedule C treatment. The exact number depends on the salary level, total income, and applicable rates.
The QBI Deduction Limit for Specified Service Fields
Section 199A allows owners of pass-through businesses, including S corporations, to deduct up to 20% of their qualified business income.10Office of the Law Revision Counsel. 26 USC 199A – Qualified Business Income Most professional fields are classified as “specified service trades or businesses,” which face special limits. The specified fields include health care, law, accounting, actuarial science, performing arts, consulting, athletics, financial services, and investment management. Engineers and architects are specifically excluded from the list and get the full benefit.
For professionals in the specified fields, the deduction depends on taxable income. Below roughly $200,000 single or $400,000 joint in 2026, the full 20% deduction is available regardless of the service classification. Between about $200,000 and $275,000 single (or $400,000 to $550,000 joint), the deduction phases out. Above the upper thresholds, professionals in the specified service fields get no QBI deduction at all. A successful attorney or surgeon well above the threshold gets zero, while an engineering firm owner at the same income gets the full amount. The salary-versus-distribution split feeds into the QBI calculation, because the deduction applies to pass-through income, not to wages paid by the corporation.
Fringe Benefit Rules for Greater-Than-2% Shareholders
Professionals who own more than 2% of an S corporation are treated differently from ordinary employees for fringe benefit purposes. Health and accident insurance premiums the corporation pays for a greater-than-2% shareholder-employee are deductible by the business, but they have to be reported as additional wages on the shareholder’s W-2.11Internal Revenue Service. S Corporation Compensation and Medical Insurance Issues Those wages are not subject to Social Security, Medicare, or unemployment taxes as long as the plan covers a class of employees rather than just the owner. The shareholder can also claim an above-the-line deduction for the premiums on the personal return, which largely washes out the added income.
Some familiar tax-favored benefits are off the table for a greater-than-2% shareholder:
- Health Reimbursement Arrangements (HRAs). The Section 105(b) exclusion doesn’t reach self-employed individuals, and the IRS treats 2%-plus shareholders the same way.
- Qualified Small Employer HRAs (QSEHRAs). Same exclusion.
- Flexible Spending Arrangements and other Section 125 cafeteria plan benefits.
For a medical practice or accounting firm whose principals were used to tax-free fringe benefits under a C corp, the S election can feel like a step back on health benefits. The above-the-line premium deduction softens the effect, but only if the shareholder or spouse isn’t eligible for a subsidized employer plan elsewhere.11Internal Revenue Service. S Corporation Compensation and Medical Insurance Issues
Keeping the Election From Terminating by Accident
S corp status can be lost involuntarily if the corporation stops meeting the eligibility requirements, even briefly. For a professional corporation, the usual trigger is an ownership change that puts shares in the wrong hands. If a deceased shareholder’s estate passes shares to an ineligible beneficiary, or if the corporation issues shares to someone who doesn’t hold the required license, the S election terminates as of the date of the disqualifying event.
Section 1362(f) gives the IRS authority to grant relief for inadvertent terminations. The corporation has to show that the termination was not intentional, that it corrected the problem within a reasonable time after discovery, and that the corporation and its shareholders will accept whatever adjustments the IRS requires. Relief comes through a private letter ruling, with a formal request and the applicable user fee.8Internal Revenue Service. Late Election Relief The practical move when a disqualifying event happens is to fix the ownership immediately and then ask for retroactive relief, rather than waiting.