Prediction markets are risky. You can lose all the money you put into a position. Only trade money you can afford to lose. Nimb shows public data and helps you place orders on Polymarket; it does not tell you what to trade, and nothing on Nimb is financial advice.
You can lose your whole stake
A share pays $1 if its outcome happens and $0 if it does not. If you buy Yes at 41% and the answer is No, the shares are worth nothing. There is no partial refund for being nearly right.
Prices are not facts
A price of 41% is what traders are willing to pay, not a measured probability. Markets can be wrong, thin, slow to react or moved by a few large wallets. Past moves, holder positions and correlations on Nimb describe what happened; they do not predict what will.
Costs eat into small edges
Polymarket's taker fee (on markets that charge one), Nimb's builder fee of 0.33% on taker orders from 11 November 2026, and the spread between bid and ask all come out of your result. A trade only pays off on average if the real chance is above the break-even shown on the ticket, not above the price. Most short-term views do not survive these costs.
Orders can fill worse than you expect
- A market order walks the order book. In a thin book it can fill at a worse average price than the last trade, up to the limit on the ticket, or only in part.
- Prices can jump on news before your order reaches the book.
- Selling before resolution depends on someone buying: the bid can be far below the mid price, or missing.
Resolution can surprise you
Each market resolves under its own written rules, through Polymarket's resolution process (UMA's optimistic oracle). The wording of the rules, not the headline, decides the result. Results can be disputed and delayed, and in rare cases can go against what most people expected. Read the rules on Polymarket before you trade.
Technology, custody and counterparty risk
- Your funds sit in your own wallet and your Polymarket wallet, as pUSD on Polygon. Smart contracts, bridges, stablecoins, wallets and the Polygon network can fail, be attacked or be paused.
- If you lose your recovery phrase, nobody, including Nimb, can recover your funds. If someone else gets it, they can take them.
- Polymarket can change its rules, fees, markets and the countries it serves.
- Nimb can be wrong or offline. If it is, your positions stay on Polymarket and you can reach them from polymarket.com with the same wallet.
Legal and tax risk
Prediction markets are restricted or illegal in some countries. In the United States, the United Kingdom, France and others, Polymarket only lets you close positions. You are responsible for following the law where you are, and for any tax on your gains.
Keep it in proportion
Treat prediction markets as a way to read the news and to act on a view you can explain, with small amounts. If trading stops being fun, or you are chasing losses, stop. Free, confidential help is available from organisations such as GamCare (UK, gamcare.org.uk) and the National Council on Problem Gambling (US, 1-800-GAMBLER).
The longer guide is risks of prediction markets; see also known limitations of Nimb's analytics.