How Business Owners Cut Their Effective Rate Below 20%
It is never one deduction. It is four or five moves that stack without undercutting each other.
An effective tax rate is total tax divided by total income, which is always lower than the marginal rate on the last dollar earned. Moving a profitable business owner below 20 percent combined generally requires four things working together: an entity structure that limits payroll tax, a retirement plan sized to the owner's age, depreciation deployed against real property, and a state pass-through entity tax election.
Effective Rate Versus Marginal Rate
These get conflated constantly and the difference matters for goal-setting. The marginal rate is what applies to the next dollar. The effective rate is total tax divided by total income, and it is always lower because the earlier dollars were taxed in lower brackets.
An owner in the 37 percent bracket is not paying 37 percent of their income. Before any planning, their federal effective rate might be 28 percent, with state and payroll tax on top. Planning works on the effective rate, and quoting a marginal rate as though it were the actual burden produces both bad targets and bad decisions.
Move One: Structure Out the Payroll Tax
For an owner-operated business, an S election limits Social Security and Medicare tax to the wages paid rather than the entire profit. At this income level, with the Social Security wage base already cleared, the saving is the Medicare component, roughly 3.8 percent including the additional tax, on the profit taken as distribution.
On $500,000 of distribution that is around $19,000. Against $800,000 of total income it moves the effective rate by roughly two and a half points. Real, but on its own nowhere near the target.
Move Two: Size the Retirement Plan to the Owner's Age
This is the heaviest lever. A solo 401(k) alone is useful. A cash balance plan stacked on top is sized actuarially by what must be funded by retirement, so the contribution capacity rises sharply with age.
An owner at 52 can frequently deduct $150,000 to $250,000 across the combined structure. Against $800,000 of income, a $200,000 deduction moves the effective rate by six to eight points by itself. Nothing else available from ordinary operations comes close.
The money is deferred rather than eliminated, and it is taxed on distribution. That still wins where the deduction comes off at 37 percent and distributions later occur in a lower bracket, and it wins on the compounding of amounts that were never taxed in the first place.
Move Three: Put Depreciation Against Real Property
With 100 percent bonus depreciation permanent under the OBBBA for property acquired after January 19, 2025, a cost segregation study on a building the owner already holds converts what would have been decades of straight-line depreciation into an immediate deduction.
On a $1,500,000 commercial building, a study typically reclassifies 20 to 30 percent of basis into shorter-lived categories, producing a first-year deduction in the $300,000 to $450,000 range. The critical constraint is whether the loss can be used: passive activity rules generally prevent rental losses from offsetting business income unless the owner qualifies as a real estate professional, materially participates in a short-term rental, or the property is used in the owner's own trade or business.
That constraint is where most of the value is won or lost, and it is why this move has to be planned rather than discovered in March.
Move Four: Elect the State Pass-Through Entity Tax
Most states now permit a pass-through entity to pay state income tax at the entity level, where it is deductible federally, rather than at the individual level where the state and local tax deduction is limited.
For an owner in a state with a 5 to 9 percent income tax, this converts a largely non-deductible expense into a fully deductible one. On $700,000 of income in a 6 percent state, that is $42,000 of state tax becoming deductible, worth roughly $15,000 federally. It requires an election, usually annually, and it is among the most frequently missed items on returns we review.
How It Stacks
Take an owner with $850,000 of profit, age 52, in a 6 percent state, who owns their commercial building.
- S-corp structure: roughly $19,000 of payroll tax avoided.
- Solo 401(k) plus cash balance plan: roughly $200,000 deducted.
- Cost segregation on the owner-occupied building: a first-year deduction usable against business income because the property is used in the trade or business.
- PTET election: state tax made federally deductible.
Each move is ordinary. None is aggressive. Sequenced together they take a low-thirties effective rate into the high teens or low twenties, and the result comes from stacking rather than from any single item.
Key Takeaways
- Effective rate and marginal rate are different numbers; plan against the effective rate.
- Retirement plan design is the heaviest single lever, and its capacity rises with the owner's age.
- Cost segregation only helps if the resulting loss is actually usable against the income you have.
- The PTET election is among the most commonly missed items on high income returns.
- Sub-20 percent comes from four moderate moves stacking, never from one large deduction.
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Frequently Asked Questions
Is a sub-20% effective rate realistic for a business owner?
For an operating business owner with real estate in the picture and a properly sized retirement plan, yes. For a service business owner with no property and no retirement plan capacity, the mid-twenties is a more realistic floor. The answer depends heavily on age, state, and whether depreciation has anything to attach to.
Does deferring tax through a retirement plan really help?
It helps when the deduction comes off at a high marginal rate and distributions later occur at a lower one, and it helps through compounding on amounts that were never taxed. It helps less if the owner expects to be in the same bracket in retirement, which is why plan design should be modeled rather than assumed.
Why can't I use my rental losses against my business income?
Rental activity is passive by default under Section 469, and passive losses generally offset only passive income. The common exceptions are qualifying as a real estate professional, materially participating in a short-term rental where the average stay is seven days or less, or holding property used in your own trade or business.
How long does it take to move an effective rate?
State elections and retirement plan contributions can affect the current year if handled before the relevant deadlines. Entity changes usually take effect the following tax year. Cost segregation can reach back to prior years through a Form 3115 catch-up without amending returns.
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