SoFi Coach took the brand promise into the hardest domain — lifetime money — and, like every LLM-era guide, must disclose that outputs may contain inaccuracies. That sentence is the only thing standing between Coach and the brand promise. MaxiFi removes it: the deterministic engine that computes each member's provably correct lifetime plan — the answer Coach can speak, cite, and stand behind with a guarantee.
The growth case →Request the briefingCoach, Composer, the one-stop-shop flywheel: SoFi is building the AI money guide faster than any consumer platform — three tuck-ins in the first half alone. What no LLM can supply is the warrantable number. The disclosure in Coach's own launch — outputs “may have inaccuracies” and are not advice — isn't a SoFi flaw; it is the truth of every generative model. It is also the gap between a guide and a guarantee.
Robinhood says powerful. Cash App says simple. The incumbents say personalized. Nobody in consumer finance can substantiate “right” — except the company that owns the engine that computes it. MaxiFi solves the lifetime plan for a member's facts and assumptions — every dollar of taxes and Social Security computed under current law, same inputs, same answer, every time, with an audit trail.
That changes what the claim is. Backed by the pedigree — thirty years of Laurence Kotlikoff's economics, taught with at MIT Sloan by Nobel laureate Robert Merton — and by the reproducible computations themselves, the accuracy claim stops being puffery and becomes a substantiated statement of fact. And determinism unlocks what a claim alone never could: a bounded Accuracy Guarantee with a defined remedy — the play that built TurboTax's franchise, never before available in planning, insurable only because the math is exact.
The substantiation regime that polices financial advertising — FINRA 2210's fair-and-not-misleading standard, FTC substantiation doctrine — protects this claim. Rivals can run vague accuracy language; what they cannot run is your claim: the specific, falsifiable, guaranteed one. Copying it without the engine is a false claim regulators, NAD panels, and Lanham Act suits will punish.
“The only money app that can guarantee its math” — advertising with a substantiation file behind it, in the voice the brand already owns.
Guaranteed-accurate lifetime planning as the premium feature — the reason membership pays for itself.
The computed plan tells each member, defensibly, when the loan, the invest account, the IRA, and the insurance genuinely improve their life — cross-sell on fiduciary-grade footing.
Members leave apps; they don't leave the company that stands behind their plan with a guarantee.
| Robinhood / Cash App | Incumbent brokers | SoFi + MaxiFi | |
|---|---|---|---|
| The advice claim | “Powerful / simple” | “Personalized” | “Right — guaranteed” |
| Behind the claim | Content + calculators | Rented Monte Carlo | Deterministic optimization, audit trail |
| Can rivals copy it? | The words, not the proof | The words, not the proof | Imitation = a false claim, policed by regulators |
One quarter of the claim behind Coach and SoFi Plus answers what no forecast can. Owning MaxiFi is the exclusive right to run that play, and to deny it to Robinhood, Cash App, and the incumbents permanently. It is a revenue line, not a legal reserve.
MaxiFi (Economic Security Planning, Inc.) uses consumption smoothing and dynamic programming to compute the single, mathematically optimal lifetime plan — solving simultaneously across Social Security strategy, federal and state taxes, Roth-conversion sequencing, withdrawal order, insurance sizing, and upside investing. For a household's facts and assumptions it solves — not guesses: same inputs, same answer, every time, with an audit trail.
Prof. Laurence Kotlikoff — William Fairfield Warren Professor at Boston University; Harvard Ph.D.; former Senior Economist, President's Council of Economic Advisers; named by The Economist among the 25 most influential economists.
Taught with at MIT Sloan by Nobel laureate Robert Merton as an “outstanding science-based lifecycle and retirement management platform” (Merton does not endorse products); featured in Bankrate's “Best financial planning software of 2025” roundup. The economics trace to Nobel-recognized lifecycle work.
Patented algorithms and thirty years of continuously maintained federal/state tax, Social Security, and benefit rules with a validation record — exactly the IP a language model cannot reverse-engineer and a build team cannot shortcut.
Larry Kotlikoff intends to stay on with the acquirer — to integrate the engine, validate the training and guarantee programs, and continue as spokesperson. The acquirer buys the engine and keeps the economist who built it.
Coach keeps the voice, the relationship, and the surface; MaxiFi computes the plan underneath — retirement, Social Security timing, Roth sequencing, insurance sizing, sustainable spend — and the guarantee ships with it. Exactly the Composer / PrimaryBid / Peach deal shape: buy the capability, ship it to the member base in a quarter. Larry Kotlikoff stays on to integrate and as spokesperson.
This is the first FINRA examination cycle to treat generative AI as a standalone topic — Rule 3110 supervision reaching the reliability and accuracy of the AI model, Reg Notice 24-09 reaching embedded third-party tools. As Coach moves deeper into advice, MaxiFi converts its answers from an examination liability into an examination exhibit: computed, verifiable, reproducible.
And the engine ships with the architecture that keeps the floor solid under an advertised claim: assumptions and law-table version disclosed on every output, customer input attestation, versioned rule tables with re-run notices on law changes, and the Accuracy Guarantee's defined remedy. The audit trail proves each customer was told exactly what was — and wasn't — promised.
We price the asset on the growth case above. The defense beneath it is a term of the deal, not the deal — and, like the claim itself, it is denied to every competitor the day it is yours.
A frontier model's retirement “smile” ran 13% too low in each of a real household's 40 remaining years against MaxiFi's computed path — dated, dollar-specific, reproducible.
Four frontier AIs sized the same father's coverage at $1.3M, $1.4M, and $3.8M — against MaxiFi's internally consistent $2.09M. Every shortcut the AIs used is programmable — and wrong.
One retirement question, three frontier engines, three different verdicts — with MIT's Andrew Lo noting these tools carry no best-interest duty. The category estimates; the divergence is the proof.
The tests publish to 145,000+ subscribers and counting — credibility no rival in the category can match, and it conveys with the acquisition.
Larry spent thirty years building what Wall Street sells to millionaires — for the members SoFi was built for. We are running a deliberately narrow process for the home that actually means it about getting people's money right.
The next step: a 30-minute briefing — MaxiFi solves a real household's lifetime plan, live, while a frontier model is asked to match it. The gap is the thesis; the funnel is the price.
Michael Kane, Ph.D., J.D. · Managing Partner, Kane & Company · FINRA / SEC / SIPC–Registered Investment Bank
Commerce@kaneco.com · 310-441-5263 · Representing Economic Security Planning, Inc.