As a fractional CFO or fractional executive, you are self-employed in the eyes of the IRS, which means you owe income tax plus the 15.3 percent self-employment tax on your net earnings, you pay it quarterly, and you can deduct the costs of running your practice. The hard part is rarely the rules. It is that your income arrives from several clients at once, and nothing pulls it together for you.
You advise companies on their finances for a living. Here is the plain version of how to keep your own just as clean, without it eating the time you should be billing.
Why fractional work is its own tax situation
You spent years inside a company with a payroll department that handled withholding, benefits, and filings invisibly. The moment you went fractional, all of that became yours, multiplied by the number of clients you serve.
A typical fractional executive runs three to five engagements at once, often on monthly retainers, each client paying separately, and most issuing a 1099-NEC at year's end. Your income is higher than most independent workers, which raises the stakes on getting the tax math right, and it lands in irregular chunks that make your real profit hard to see at any given moment. That combination, high income plus multiple concurrent payers, is exactly the situation for which generic small-business tax advice was not written.
The taxes you actually owe
Two layers stack on your net earnings.
Self-employment tax is the one that surprises former employees the most. It is a flat 15.3 percent covering Social Security and Medicare, and you pay both the employee and employer halves now that no company splits it with you. For 2026, the Social Security portion applies to the first 184,500 dollars of net earnings.
Income tax is charged on top of your regular bracket on your profit after deductions. Because fractional executives often earn well into six figures, you are usually in a higher bracket, which makes capturing every legitimate deduction worth real money.
And because no client withholds for you, the IRS expects quarterly estimated payments in April, June, September, and January. Setting aside 30 to 35 percent of each retainer as it arrives keeps those payments from becoming a scramble.
Deductions specific to a fractional practice
Your write-offs are the ordinary and necessary costs of running your practice:
- A home office used regularly and exclusively for your work
- Travel and mileage to client sites
- Software, financial tools, and subscriptions you run your engagements on
- Professional development, certifications, and memberships
- Professional liability insurance
- The business-use portion of your phone and internet
- Self-employed health insurance premiums
The rule that makes these work is documentation. A deduction you cannot find at tax time is a deduction you do not get, which is why capturing each expense as it happens beats reconstructing a high-earning year from memory.
The entity question is worth knowing about
Once your net profit is consistently high, which is common for fractional executives, it is worth understanding whether electing S-corp status could lower your self-employment tax. It is not right for everyone, because it adds payroll and filing costs, but at your income level, the math can favor it. Our guide on LLC versus S-corp for consultants walks through where the line usually falls.
How Sumly handles it
The core problem for a fractional executive is not any single rule. It is that your income and expenses span several client relationships and never add up to one picture on their own.
Sumly brings the money side of your practice into one place. As retainers and payments arrive from each client, income gets organized, and your practice expenses get categorized as they happen, so your real profit and your deduction picture stay current instead of being rebuilt before each quarterly deadline. You see your whole practice at a glance, not five engagements you have to mentally reconcile.
And because Sumly is backed by in-house licensed tax professionals, the structure you work inside reflects real tax rules, not a generic formula. When a genuine question comes up, like whether your income level makes an S-corp election worthwhile, there are actual licensed professionals behind the product. To be clear about what the tool does: it organizes and categorizes your finances so they stay clean and current. It does not replace your judgment, it gives you back the hours you would otherwise spend assembling the picture yourself.
Frequently asked questions
Do fractional CFOs pay self-employment tax? Yes. Unless you have elected S-corp status, your net earnings as a fractional executive are subject to the 15.3 percent self-employment tax, on top of income tax.
Should a fractional executive form an LLC or an S-Corp? Many start as a sole proprietor or single-member LLC and consider an S-corp election once net profit is consistently high, because it can reduce self-employment tax. The right answer depends on your numbers and the added costs.
How much should I set aside for taxes as a fractional CFO? Because fractional income often lands in a higher bracket, setting aside 30 to 35 percent of each payment is a safer target than the 25 to 30 percent rule of thumb for lower earners.
Keep your own books as clean as your clients'
You bring order to other companies' finances. Your practice deserves the same.
See what you should be setting aside with the Sumly tax calculator, then let one organized system keep your retainers, deductions, and quarterly math up to date all year.
Ready to spend less time on admin?
Sumly is the easiest way to track expenses, keep clean books, and run your business.