Solo 401(k) vs SEP IRA: the retirement account gap freelancers keep missing

Every issue so far has been about what to hand an agent today. This week is about something an agent won't fix for you: picking the right retirement account in the first place. Get the account wrong and no amount of automation on top of it closes the gap back up.

This week in the agent economy

• At a House Financial Services Committee hearing, Circle's Heath Tarbert told lawmakers that AI agents need programmable, always-on payment rails — and fielded questions on the identity controls required when software initiates a transaction. What it means for you: this is the same identity question this newsletter keeps returning to, now live in a congressional hearing room. The US doesn't have a MAS- or FCA-style framework yet, but lawmakers are actively asking the right questions.
• Rocket Money launched "Rowan," an AI agent that manages subscriptions, budgets, and bills through text-message conversations. What it means for you: this is a mainstream consumer finance app putting an agent directly into subscription tracking — the same Tier 1 task (read, categorize, flag) this newsletter has called safe since issue one. Worth trying if you already use Rocket Money.

The deep dive: Solo 401(k) vs SEP IRA

Most freelancers who set up a retirement account at all default to a SEP IRA, usually because it's the one their bank or brokerage surfaces first. It's simple to open and simple to fund. It's also, for most solo operators, the account that lets you save the least.

Where the two accounts actually diverge

A SEP IRA lets you contribute up to 25% of your net self-employment earnings, capped at the annual IRS limit. A Solo 401(k) lets you contribute as both employee and employer: an employee deferral (up to the standard 401(k) limit, plus a catch-up if you're 50 or older) on top of the same roughly-25%-of-earnings employer contribution a SEP allows. That employee-deferral layer is the whole gap.

• The concrete difference. At $120,000 in net self-employment income, a SEP IRA tops out around $24,500 in contributions for the year. A Solo 401(k) covering the same income and the same person can reach roughly $288,000 in combined contribution room over a working stretch where the SEP stays flat — the employee-deferral layer compounding year over year is what separates the two, not a one-year gap.
• Where a SEP still wins. Simplicity and irregular income. A SEP IRA has essentially no paperwork to maintain and no annual filing once assets grow, which matters if your income swings hard month to month and you want one less thing to manage.
• Where a Solo 401(k) wins. Anyone consistently clearing enough income to make the employee-deferral room worth the extra setup — which, for most freelancers earning a full-time income solo, is more often than the SEP's popularity would suggest.

Why this is squarely a Tier 1 problem, not a Tier 3 one

None of this involves handing an agent access to move money. It's a research and comparison task — reading your own income numbers, checking them against both accounts' rules, and flagging which one actually fits. That's exactly the kind of task issue three called safe to delegate: an agent can lay out the two scenarios with your real numbers, but the account-opening decision itself is still yours to make once, not something to automate away.

The mistake isn't picking the wrong account forever — it's not knowing there was a real choice to make, and staying on autopilot with whatever the sign-up flow suggested first.

— FinAgentHub