Questions about prediction markets
What people ask, answered without hedging — including where the money comes from. For the meaning of a single word, the glossary is shorter.
The basics
What is a prediction market?
A market in contracts that pay $1 if something happens and nothing if it does not. Because the payout is fixed, the price becomes a probability: a contract trading at 63 cents is the market saying roughly 63 percent. People trade them the way they trade shares, and the price moves as opinion and evidence move. The glossary defines the rest of the vocabulary.
Are these odds forecasts?
They are prices, and this site does not produce any of them. Every number here is read from Polymarket and Kalshi and passed through unchanged. Nothing on this site is a recommendation, and a price is only ever what people were willing to pay a moment ago.
Are prediction markets accurate?
Reasonably, and better on busy markets than quiet ones. Money on the line is a real incentive to be right, so a heavily traded market is usually hard to beat. A thin one is a handful of opinions with a price attached. The known systematic error is that unlikely outcomes trade a little too high — see favourite–longshot bias in the glossary.
Why do Polymarket and Kalshi show different odds for the same event?
Usually because the two questions are not quite the same one. Different wording, different resolution sources and different deadlines all move a price, and the traders on each venue are not the same people — many cannot legally reach both. Read both sets of rules before treating a gap as an opportunity.
Reading this board
What do the size and colour of a bubble mean?
Size is whatever you have sorted by — volume unless you change it — and colour is the probability of the leading outcome. So changing the sort changes what the whole picture is telling you. Sizes are scaled to fit the screen: the ordering is exact, the ratio between two bubbles is not.
What does “Heating up” mean?
It is this site's own score for markets doing something unusual right now, built from money arriving faster than that market's normal and the probability actually moving. It exists because sorting by volume shows the same twenty questions every day — lifetime volume barely changes overnight.
What is “Whales’ favourites”?
Markets holding at least five separate positions worth $10,000 or more. It counts positions rather than ranking by the biggest one, because the biggest single position on this board turned out to be one market maker holding the same three-million-dollar bet against three different candidates. Polymarket only — Kalshi publishes no holder data. Only counts and sums are stored: no wallet, no name, no profit.
How often is the data updated?
Odds and volume every 15 minutes. The individual market pages rebuild hourly, the large-position counts four times a day, and price history is filled in overnight. The board shows when it last refreshed, and reloads itself while you leave it open.
Which markets appear here?
Every open market both venues publish, with no editorial selection at all — the ordering is arithmetic on volume and activity. Markets that have resolved drop out. You can hide any market or mark it a favourite with a right-click; those choices live in your browser and are never sent anywhere.
Can I put this board on my own site?
Yes, free and without an account. The embed builder builds the iframe for you: pick a category, a venue, a sort and a size, and copy the snippet. The embed carries no analytics and sets no cookies.
Money, data and the small print
How does this site make money?
Sponsorship and referral. Jameye is a paid sponsor and appears in the Trade menu marked as one; the links to Polymarket and Kalshi may carry a referral code. Every such link is tagged so browsers and search engines can see it. None of it touches which markets appear or what order they are in — that is computed from volume and activity before any of this is applied, and there is no way to pay for a place on the board.
Is trading on these markets legal where I live?
It depends on where you are, and this site cannot advise you. Prediction markets are restricted or prohibited in a number of countries, and the two venues serve different places on different terms. Check the venue's own terms and your local rules before opening an account. Nothing here is financial or legal advice.
Do you track me?
The site uses Google Analytics to count visits. Your favourites, hidden markets and settings are kept in your own browser and are never sent anywhere — clearing your browser data clears them. The embeddable version carries no analytics at all, because publishers are promised exactly that.
Is the board available in other languages?
English, German and Spanish, each with its own address — the live board you are reading about is at the language you chose. Market questions are translated too. The individual market pages stay in English, because their value is ranking for the question as the venue worded it.
Not answered here? Write to [email protected]. Definitions of the individual terms are in the glossary.