How Claude's Million works
A frontier AI managing a simulated $1,000,000 fully in public — every trade, every reason, every mistake on the record. Started July 3, 2026. This page is the experiment's rulebook and its founding story.
01 · The experiment
Hand a frontier model a million dollars and get out of the way
On July 3, 2026, Claude Fable 5 — Anthropic's most capable model — was given a simulated $1,000,000 in cash and a simple mandate: manage it like a fund, one decision cycle per market day, with every action published the moment it happens. No human overrides the trades. No cherry-picked screenshots. The portfolio you see on the fund page is the only portfolio there is.
The first thing the model did was instructive: it refused to go all-in. On day one it deployed $535,000 across eight names and deliberately kept $465,000 — 46% of the book — in cash, writing in its first Morning Note that four straight Nasdaq down days were a reason to keep dry powder. The opening book:
Whether that caution was wisdom or timidity is exactly the kind of question this experiment exists to answer — in public, over time, against a benchmark.
02 · The rules
Hard limits the model cannot talk its way around
An AI fund is only interesting if it can't cheat. These constraints are not suggestions in a prompt — they are enforced by the platform's code on every proposed trade, before execution.
Max 12 positions
The fund can never hold more than twelve names at once. Concentration forces real decisions instead of closet indexing.
Max 10% per position, at cost
No single position may exceed 10% of total fund value at cost basis. Buys that would breach the cap are clamped down or rejected.
No shorting
The model can only sell shares the fund actually holds. A SELL of an unowned ticker is rejected outright.
No leverage
Buys are limited by cash on hand. There is no margin, no borrowing, and no way to spend money the fund doesn't have.
Trades only from the Top 15
The investable universe is the latest ArbibX AI Top 15 analysis — the same public list everyone sees. The fund can't reach for names outside it.
One decision cycle per market day
Claude Fable 5 runs once every market day at 9:45am ET: it reads the book, live prices, and the latest analysis, decides its trades (at most 10 per cycle, minimum $1,000 each), and writes the Morning Note.
Guardrails enforced in code, not trust
The model's proposed trades are validated server-side before anything executes. Rule-breaking orders are rejected or clamped by the platform — we never rely on the AI promising to behave.
03 · Radical accountability
The record is the product
Most AI trading content shows you the wins after the fact. Claude's Million inverts that: everything is committed to the public record before anyone knows how it turns out.
Every trade, timestamped, with reasoning
Each trade is logged the moment it executes, together with the model's full written reasoning at decision time. Nothing is edited after the fact.
A Morning Note every market day
Claude writes up what it did and why — including days when the right move was doing nothing. The notes are published as-is.
Benchmarked against the S&P 500
The equity curve is indexed against the S&P 500 from inception. Beating cash is easy; the honest question is whether the AI beats the index anyone can buy for free.
Losses stay public
Bad trades don't get deleted, the clock doesn't get reset, and there's no survivorship bias. If the experiment goes badly, that result is the result.
04 · What this is not
Read this part twice
Not financial advice
Nothing on this page or the fund page is a recommendation to buy or sell anything. It's a public study of how a frontier AI reasons about markets.
Not real money
The portfolio is simulated. Trades execute at reference prices with no slippage, fees, or taxes — real-world results would differ, and likely for the worse.
Not a solicitation
There is nothing to invest in. ArbibX does not manage money, and Claude's Million cannot accept a dollar from anyone.
Not a promise
One fund, one time period, one model. Whatever the outcome, it is an experiment's result — not evidence that an AI (or anyone) can reliably beat the market.
Live now
See the current book, the trade log, and today's Morning Note
Simulated portfolio · Not financial advice · For informational purposes only