Before you trade, Nimb runs up to five checks on the market you have open: whether the last day's move was unusual, whether the order book is thin, whether one wallet dominates, how close the deadline is, and the break-even chance including fees. They appear in the "Before you trade" box, right above the order ticket.
Why do the checks exist?
Most losses in prediction markets do not come from bad luck on a fair price. They come from paying too much: buying into a spike that reverts, a thin book that fills you badly, a market one holder can push around, or a price that needs fees on top before it pays. The checks turn the most common of these into plain sentences, one line each, so that market reading happens before the order, not after. A highlighted line is a reason to look closer, not an instruction.
| Check | Threshold | Highlighted when | What to do |
|---|---|---|---|
| Unusual move | 24-hour move vs a typical day over 30 days | Move of 2× a typical day or more (and at least 1 point) | Find the news first. Do not chase a move you cannot explain. |
| Thin order book | Liquidity in the book | Under $5,000 | Trade small, or use a limit price. |
| One wallet dominates | Largest wallet's share of the top holders' value | Over 35% | Look at that wallet. Expect sharp moves if it sells. |
| Deadline | Days until the market resolves | 7 days or fewer | Read the rules. Check the resolution source and time zone. |
| Break-even | Chance needed to profit, fees included | Never; always shown | Ask whether you know something the market does not. |
The one-wallet line only appears when it applies; the others appear on every market with the data to run them.
What counts as an unusual move?
Nimb takes the price change over the last 24 hours and divides it by the market's typical day: the standard deviation of its 24-hour changes over the past 30 days.
| Situation | Product sentence |
|---|---|
| 2× a typical day or more (highlighted) | "Moved +6.0 points in 24 hours, 2.4× a typical day. Unusual moves often follow news: check what happened before you follow it." |
| Under 2× | "Moved +6.0 points in 24 hours, within a normal day for this market." |
| Under 1 point | "Flat over the last 24 hours." |
An unusual move is not a signal to follow. Fast moves often overshoot and partly revert, and if the news is public, the price may already include it. Read the move on the price chart and the money flow bars: a jump backed by heavy buying is different from one made by a single order.
Will my order fill near the price?
| Liquidity | Product sentence |
|---|---|
| Under $5,000 (highlighted) | "Thin order book ($3.2k). A large order will get a worse price than 41%; use a small amount or a limit price." |
| $5,000 or more | "About $48k sits in the order book, so orders up to around $4.8k should fill close to 41%." |
The "around 10% of the book" figure is a rule of thumb. A thin book means your own order moves the price against you, and selling later costs the same again. Spread and order book depth has worked examples.
Why does a concentrated holder matter?
Nimb adds up the value held by the market's top holders, after netting wallets that hold both Yes and No. If the largest wallet holds more than 35% of that value, the box says:
One wallet holds 52% of the top holders' value. A single big seller could move this market.
It matters for two reasons. First, if that wallet sells, it can push the price down faster than the book can absorb, whatever the news. Second, a price held up by one large buyer reflects one opinion more than a crowd's. The wallet may be well informed or not; its size does not tell you which. See holders and wallet lines for how to look it up.
Why does the resolution date matter?
| Situation | Product sentence |
|---|---|
| 1–7 days (highlighted) | "Resolves in 5 days. Money in this market is locked until then unless you sell." |
| More than 7 days | "Resolves in 24 days. Money in this market is locked until then unless you sell." |
| Same day (highlighted) | "Resolves today." |
| Deadline passed | "The deadline has passed; the market is waiting for the official result." |
Close to the deadline, one piece of news can take the price to 0% or 100% in minutes, and there is little time to recover from a wrong call. Far from it, your money is tied up for weeks or months; selling early means selling at whatever the bid is then. When the deadline has passed, the result is decided by the resolution process, not by trading; read how markets resolve.
What is break-even probability?
Break-even probability is the chance an outcome must really have for a trade at the current price to come out even after fees. The box always shows it for buying Yes:
Buying Yes at 41% only pays off if the real chance is above 42.2% (fees included). Ask yourself whether you know something the market does not.
It is the price per share plus fees per share, as a share of the $1 payout. Polymarket charges a taker fee in most categories, equal to a category rate × price × (1 − price) per share. Nimb adds a small builder fee, included in the price you see. For a Yes share at 41%:
| Category | Polymarket rate | Polymarket fee per share |
|---|---|---|
| Geopolitics | 0 | 0.00¢ |
| Politics, Finance, AI & Tech | 0.04 | 0.97¢ |
| Sports, Climate & Culture | 0.05 | 1.21¢ |
| Crypto | 0.07 | 1.69¢ |
The figure in the box includes all fees, Polymarket's and Nimb's, so it always sits a little above the price. The fees and all-in pricing page explains how fees fold into the shares you receive, so the amount you type is all you pay.
The question under it is the real check. The market has already priced what most traders know. Paying 42.2% for a 41% chance only makes sense if you have a reason to think the true chance is higher: information or analysis the price does not reflect. Nimb's docs call that alpha, and most apparent edge turns out to be noise or fees.
What should I do when a check is highlighted?
- Read the line. Each one names the risk and the usual fix.
- Look up the cause. News for a move, the book for liquidity, the wallet for concentration, the rules for a deadline.
- Size down or wait. A smaller order, a limit price or no trade are all fine answers.
- Count the highlights. One highlighted line is common. Two or three on the same market (a fast move in a thin book held by one wallet) is a market that can move a long way against you.
No check replaces reading the market yourself, and a market with no highlighted line is not a safe one. Prediction markets are risky: you can lose your whole stake. Nothing here is financial advice. Read the risks of prediction markets and check whether trading is allowed where you live. The checks are the last step of how to read a market.
From reading to execution
The checks close the market reading, and the box sits directly above the order ticket so the last thing you read is the break-even. The ticket then repeats it in its own sentence, with the shares and payout for the amount you type.
Last reviewed 2026-11-07 · Data from Polymarket · Not financial advice · Nimb is not affiliated with Polymarket.