About Arena
Arena is trading tools for prediction markets. In the sandbox you trade real, live market prices with paper dollars, and a trade held to the end settles against the real outcome, so you can test a strategy under real conditions and build a graded track record. When you choose, you send live orders to Kalshi or, outside the US, Polymarket International with your own venue credentials: real money at the venue, under the venue's rules and terms. Arena is not a broker and never holds your funds.
Real prices, a paper balance
Every price you see in Arena comes from real prediction markets, including Kalshi and other public venues. What you trade with is paper dollars in Arena’s sandbox. Your balance carries over, and after you turn resets on in Settings, you can reset it once every 30 days. Sandbox balances have no cash value and can never be deposited, withdrawn, or redeemed for cash or prizes. Paper trades fill in Arena’s own ledger and are not sent to any venue.
Live orders
Live orders go to Kalshi and, outside the US, Polymarket International, with your own venue credentials, saved in Settings. A ProphetX account can be connected, and ProphetX orders are switched off. A live order is sent with your own venue credentials and is real money at the venue, under the venue's rules and terms. Arena is not a broker and never holds your funds. Paper stays the default: an order is live only when you choose live for that order.
How a paper trade works
- You choose a market, a side (Yes/No), and a number of contracts.
- Market orders fill at the live ask when you buy and the live bid when you sell. Limit orders name a price and fill at that price or better, or rest until they do.
- Every fill is priced on our server from the live market, not by the app. One contract settles for $1.00 if your side is correct, $0 if not.
- When the underlying real-world event resolves, your position settles automatically from that real outcome (the same result the underlying market pays on).
How we score you
Net worth is your spendable balance plus open stakes at cost plus money held by resting orders. Leaderboards rank profit: all time since September 1, 2026 across every reset, and the last 30 and 90 days. Open positions count at cost, so opening one never changes your profit, and resets show on every row. Only public profiles are listed: accounts are private until their owners make them public. Arena also measures genuine forecasting skill (calibration, Brier-based accuracy, and closing-line value), so being right on purpose is rewarded, not just getting lucky.
The full model, from fills to settlement to ranking, is in How Arena fills, grades and ranks.
About the data and AI picks
Prices are indicative and may be delayed relative to the source exchange. Market data remains the property of its respective owners. Arena’s AI picks are model-generated forecasts published for entertainment and education. They are not financial or investment advice.
Independence
Arena is an independent product of ZBGC LLC. We name Kalshi, Novig, Polymarket and ProphetX to attribute the data we display, and Kalshi and Polymarket International as the venues a member’s own live orders go to.
Which Arena is this?
Arena Predictions (arena-predictions.com) is not Meta’s reported Arena app, the Prediction Arena benchmark or LMArena.
The short version
Arena is an entertainment and self-improvement tool for people who love prediction markets. It is not a licensed gambling operator, bookmaker, financial broker, or investment advisor, and it is intended for users 17 and older.
Read the Terms of Use and Privacy Policy, or get in touch.