The spread is the gap between the best price a buyer is currently willing to pay and the best price a seller is willing to accept. It's the immediate cost of getting in and out of a position — if you buy and instantly sell, the spread is roughly what you lose.
Why it matters more on longshots
A spread in cents is easy to read wrong, because the same number means very different things at different prices. A 3¢ spread on a market trading at 50¢ is small — about six percent of the price. The same 3¢ spread on a 6¢ longshot is half the price. You'd need the market to move dramatically in your favour just to break even on the cost of entry.
That's why Edge Radar shows spread as a percentage of price, not just in cents — so you can compare the real cost of entry across markets at very different price levels.
How to use it
Treat a wide spread relative to price as a warning that the market is thin or neglected. It doesn't mean avoid it — sometimes the neglect is the opportunity — but it does mean the price you see isn't the price you'll get, and you should size accordingly.
FAQ
What is the spread on a prediction market?
The spread is the difference between the highest price a buyer will pay and the lowest price a seller will accept. It represents the cost of entering and exiting a position immediately.
Why does spread matter more on longshots?
A fixed spread is a larger share of a low price. A 3¢ spread on a 6¢ market is half the price, but on a 50¢ market it is only six percent — so the same spread eats far more of your expected value on a longshot.