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About Margin Call — Free Stock Market Trading Simulator

MARGIN CALLv0.48.0
Free · No account · Runs in your browser
Most trading games move prices at random. This one simulates the economy that moves them.

Rates rise, so leveraged companies pay more to service debt, so earnings fall, so the price falls. That chain is modelled end to end — which is why the lessons transfer.

Sectors
12
Asset classes
7
Accounts required
0

What is actually simulated

The macro economy

GDP, inflation via the Phillips Curve, unemployment via Okun’s Law, and the Fed rate via the Taylor Rule. Each one feeds the next.

Company fundamentals

Quarterly earnings, debt service, and Merton distance-to-default — so bankruptcies happen for reasons you can see coming.

Volatility that clusters

GARCH(1,1) with a shared factor model. Quiet weeks stay quiet; correlations converge on 1 when the VIX passes 40.

Options priced properly

Black–Scholes with live Greeks and an implied-vol surface that crushes about 30% the morning after earnings.

Politics with consequences

Elections, legislation and lobbying apply real sector modifiers. A bill at floor vote is priced before it passes.

Rivals that read the cycle

Value, momentum, day-trading and raider strategies that react to volatility and the economy, not to you.

Questions people actually ask

Is it free?

Entirely. No account, no download, no payment, no ads.

Do you keep my data?

Your entire game lives in your browser. There is no account to leak, and clearing site data deletes the save permanently.

Will it teach me real trading?

It teaches the concepts — reading a chain, sizing a position, what a rate decision does to a sector. It is not advice, and it is not connected to real prices.

Does it work on a phone?

Yes — a separate touch interface, not a squeezed desktop. Any modern browser.

Is it multiplayer?

Single-player against five to ten AI rivals, depending on difficulty, plus an optional daily-challenge board.

What you can trade

Stocks · Options · Corporate bonds · Crypto · Forex · Prediction markets · Real estate

Plus founding a company, taking it public, running a hedge fund, and playing across generations.

What it runs on

Any current browser on desktop, tablet or phone. Nothing to install, nothing to sign into.

Where your save lives

In your browser, in IndexedDB. It never reaches a server — which also means clearing site data deletes it for good.

Who made it

Built by Simon Coombes as a side project. Free, no ads, no account, and no plan to add any.

Report a bug
Not financial advice

Every company, price and data point is invented. Simulated results say nothing about real markets.

Release notes

Nine releases since March 2026
v0.48.0
Current

IPOs you can actually get into. When a listing opens its book, indicate for shares from the offer page — allocation odds shown up front, nothing charged until you’re filled, and your allocation prints on the first trading day.

Your company can invest too. Founded companies at Series B (or a $10M valuation) can open an investment division: trade the market from the corporate treasury, and acquire other companies outright — every confirm shows the company’s cash, not yours.

Alerts you can manage. Mute, re-arm, dismiss, and delete alerts right from the list. Triggered alerts can finally be acknowledged instead of staring at you forever.

Settings on the big screen. Appearance, sound, accessibility, and save export/import now live on the Help page on desktop — including full save backup and restore.

v0.45.0Honest price attribution, the SEC and trade-history fixes, and release notes that publish themselves.August 2026
v0.44.0Crowd flow, fund-like rivals, whale block trades, and the card-is-the-setup homepage.August 2026
v0.43.0Stationary price model, live order book, plain-language simple mode by default.July 2026
v0.38.0Simple treatment extended across every reachable table, panel and quote view.June 2026
v0.32.0Chapters removed — the narrative beats interrupted the market rather than commenting on it.June 2026
v0.27.0Simple mode became the default and the daily challenges were retired.June 2026
v0.20.0Annual review set-piece, realised P&L on stock trades, and the realised-trades panel.June 2026
v0.19.0The Floor Amber redesign was reverted to the green-phosphor CRT terminal.June 2026
v0.8.0Command palette, named AI rivals, additional themes and save export.May 2026
v0.5.0Economy rebalanced — faster mean reversion, wider credit spreads, more bankruptcies in distress.March 2026
v0.1.0First release — 108 companies, the macro economy, the price model and founder mode.March 2026