A stale price, an empty order book, different tokens under one ticker — where untradeable percentages come from.
The most common beginner question sounds like this: «I can see a 40% spread — why isn't everyone taking it?» The answer is usually unpleasant: the spread is not there. There is a number with no trade behind it.
Here is where numbers like that come from — and how we filter them out.
The price is stale
The exchange gave out a last price and went quiet: there have been no trades on that pair for an hour, and the number just hangs there. Compare it against a live price on another venue and you get a gap the market does not have.
The cure is not a filter on the number but attention to when the price last changed, and whether there are any orders under it.
There is no size under the price
The price is honest, the book is empty. An 8% spread exists for exactly as much size as sits in a single order — which usually means a few hundred dollars.
We discard pairs where the book is dead on both sides: the difference is there, you cannot get into it.
One ticker, different tokens
The classic that breaks more tables than anything else. LIT on one exchange and LIT on another can be two different projects with prices that differ twofold. Formally a 90% spread; in practice you are comparing an orange with a bus.
Telling them apart by name is useless. They have to be told apart by the token contract and by the registry id — and where there is no proof, a simple rule applies: a price an order of magnitude away from every other venue almost certainly belongs to a different asset.
The spread lives for two seconds
Real dislocations happen too, but they close faster than a person can open a second tab. Showing that as an «opportunity» is lying.
So we only emit an event if the spread has held for at least 30 seconds straight. Flicker does not reach the table.
One exchange against everyone
Sometimes a single venue holds the whole spread up while the others agree with each other. That is not always a phantom — but it is always worth a look: more often it is a stuck price than a market opportunity. We flag those cases right in the alert.
What this means for you
The number in the table is not a promise but a candidate. Before trading it is worth checking three things: whether there is size under the price, whether withdrawals are open on both exchanges, and whether a single venue is holding the whole spread up.
We do our best to let less rubbish through. But the last filter is always yours.