Founders & solopreneurs · Pillar

The AI Solopreneur Tax Stack: Entity, Retirement, §199A, §174, and Nexus

High-margin solo businesses — AI agencies, indie SaaS, paid newsletters, info-products, consulting — sit on the most usable tax leverage in the U.S. code. Most of it is left on the table. This is the full stack, in the order it should be installed.

By The Empower Capital Team · Updated May 3, 2026 · ~12 min read

Layer 1 — Entity selection

The entity is the multiplier. Every other layer either compounds correctly because the entity is right, or partially defeats itself because the entity is wrong. Three live choices for most solopreneurs:

• Schedule C / single-member LLC. Default treatment for a solo business. All net profit hits self-employment tax (15.3% on the first ~$170K of earnings, plus the additional Medicare 0.9%). Simplest to operate; most expensive on SE tax once you scale.
• S-corporation election. An LLC or corporation that elects S-status under Form 2553. The owner takes a reasonable salary (subject to FICA), and remaining profit flows through as distribution (not subject to SE tax). The savings can be substantial — typically meaningful once net profit clears roughly $80K — but you take on payroll, separate filings, and a real reasonable-comp obligation.
• C-corporation. Right when you intend to raise institutional capital, qualify for §1202 QSBS, and accept the double-tax tradeoff. Wrong for most cash-flow solopreneurs.

The honest break-even for an S-election sits around $80K of net profit, but the right answer depends on payroll cost in your state, retirement-plan ambition (S-corps cap employer Solo 401(k) contributions on W-2 wages, not pass-through profit), and the audit-defense cost of documenting reasonable comp. The decision should be modeled with three years of projected revenue, not ruled on a forum-post heuristic.

Layer 2 — Retirement plan stack

This is where the highest-leverage solopreneur shelter actually lives — and where the conventional preparer typically stops at "open a SEP." The full stack:

• Solo 401(k), employee deferral. Up to the annual elective limit (~$23K under-50, ~$30.5K with catch-up) of W-2 wages or SE income, depending on entity type. Pre-tax or Roth.
• Solo 401(k), employer non-elective. Up to 25% of W-2 wages (S-corp) or ~20% of net SE earnings (Schedule C / LLC). Combined with employee deferral, the total cap reaches the annual §415 limit (~$69K under-50, ~$76.5K with catch-up).
• Mega-backdoor Roth. If your Solo 401(k) plan document permits after-tax contributions and in-plan Roth conversions, you can stack additional after-tax dollars up to the §415 limit and convert them to Roth — creating tens of thousands of additional Roth space annually. Most off-the-shelf Solo 401(k)s do not allow this; you need a custom plan document. We use providers that do.
• Defined-benefit (cash-balance) plan, layered on top. For older founders with consistent high income, a DB plan calculates required contributions actuarially based on a target retirement benefit. Annual contributions can run from $50K to $200K+ depending on age and income. Combined with a Solo 401(k), founders in their 40s and 50s can shelter $200K–$300K+ per year, fully deductible.

The DB plan is not exotic and not aggressive — it is a standard ERISA-qualified plan used by professional firms for decades. The reason most solo founders never set one up is that their preparer never raised it.

Layer 3 — §199A / QBI optimization

The Qualified Business Income deduction allows owners of pass-through businesses to deduct up to 20% of qualified business income, subject to limits. For solopreneurs the relevant questions are:

• Are you an SSTB? "Specified service trade or business" — consulting, financial services, athletics, performing arts, and "any trade or business where the principal asset is the reputation or skill of one or more of its employees." This last phrase has caught a lot of solo consultants and creators in audits. Above the income thresholds, SSTBs phase out of the QBI deduction entirely.
• Are you above or below the threshold? Below the income threshold (~$383K MFJ in 2026), the QBI deduction is generally available without further wage/UBIA limitations. Above it, you need W-2 wages or qualified property to support the deduction — which is where the S-corp wage decision compounds.
• What is "qualified business income"? Generally, ordinary trade or business income — not capital gains, dividends, or interest. For a solo SaaS or consulting business, almost all your operating profit qualifies. For a creator monetizing across YouTube, sponsorships, and royalties, the analysis can split.

If you're an S-corp owner above the threshold, the wage decision is now a three-way optimization: minimize SE tax (push wages down), maximize retirement-plan capacity (push wages up), maximize QBI deduction (find the wage that just clears the W-2 wage limit). Spreadsheets, not heuristics.

Layer 4 — §174 software-development capitalization

Under the post-TCJA §174 regime, software-development costs and other research expenditures are no longer immediately deductible. They must be capitalized and amortized over five years (fifteen years for foreign research). For founders building software products this is real cash-tax pressure — particularly in the early high-spend years before revenue ramps.

Practical implications:

• Track your §174 expenditures separately from ordinary §162 operating expenses. Categorization matters.
• The first-year deduction for a §174 expenditure is half-year convention amortization — meaning year one only deducts ~10% of the cost, not 100%.
• Form 4562 reports the amortization schedule. Workpapers should document why each cost was classified as §174 vs. §162.
• If a retroactive §174 fix is enacted (legislative attempts continue), you'll want clean records to claim the relief. Build the schedule now even if the rule changes later.

Honest disclosure: a lot of solo preparers are simply ignoring §174 for small software builders. That's a position. It's not a defensible one.

Layer 5 — Multi-state nexus (sales and income)

If you sell SaaS, digital products, courses, or AI services, your customer base is almost certainly in multiple states. Two distinct nexus questions follow:

• Sales-tax nexus. Post-Wayfair, every state can require remote sellers above an economic threshold (commonly $100K of sales or 200 transactions in the prior year) to register, collect, and remit. SaaS taxability varies — roughly half of states tax it, with delivery-method nuances. We assess your exposure, register where required, and recommend an automation tool sized to your transaction volume (TaxJar, Anrok, Avalara, depending on stack).
• Income-tax nexus. Different question, separate analysis. Some states impose income tax on remote sellers above a threshold even without physical presence. The Multistate Tax Commission's factor-presence standards influence this. For most pure-digital solopreneurs the income-tax exposure is limited to your home state, but as you scale, it warrants annual review.

The reason this matters: states do not send a notice when you cross a threshold. They send a notice — usually with retroactive penalties and interest — when they discover you crossed it. Voluntary registration and Voluntary Disclosure Agreements (VDAs) are dramatically cheaper than waiting.

Putting it together: a representative stack

An illustrative single-member solo founder running an AI consulting practice, $400K revenue, $300K net profit, age 38, single, California resident:

• Entity. S-corporation election. Reasonable comp study supports a $130K W-2 salary; remaining $170K flows as distribution exempt from SE tax. Estimated FICA savings vs. Schedule C: ~$13K/year.
• Retirement. Solo 401(k) with after-tax + in-plan Roth provisions. Employee deferral ($23K) + employer non-elective (25% × $130K wages = $32.5K) + mega-backdoor after-tax conversion to fill to §415 cap (~$13.5K). Total annual Roth + pre-tax shelter: ~$69K.
• QBI. Above the threshold and likely SSTB-coded for "consulting." Deduction phases out — model a wage adjustment to confirm whether crossing the SSTB exception threshold is achievable.
• §174. If they're also building any software (their own internal AI tool), track §174 expenditures separately even if amounts are modest.
• Nexus. Pure consulting services with engagement letters in multiple states — generally service revenue sourced to client location for income-tax purposes; sales-tax exposure typically limited to states that tax consulting (uncommon).

Roughly $20–30K of annual tax savings, $69K of new retirement shelter, and a documented audit defense — for a setup cost that pays for itself in year one and compounds for the life of the practice.

Where this guide stops

This is the framework. The real engagement is in the numbers — which require your actual revenue, expense, state, and personal-life facts. A 15-minute discovery call surfaces the highest-leverage two or three moves; the engagement implements them.