Pool betting: a price that does not exist until the event starts

In a pool, all stakes on a market are collected, a deduction is taken, and what remains is divided among the winners. There is no fixed price: what you are paid depends on how much money ended up on your selection relative to everything else, and it is not known when you bet.

Pools transfer all the risk to the customers and none to the operator, whose revenue is the fixed deduction rather than a margin on prices. That is why the deduction can be quoted openly and why it is often much larger than a bookmaker's margin — there is no competitor quoting a better price on the same pool, because the pool is the market.

It does not mean pools are always worse. A pool with unusual money in it can pay more than any bookmaker will, and on some events a pool is the only market with real depth.

The problem arrives next. Indicative returns displayed before the off are read as prices. They are estimates of a ratio whose denominator is still growing, and the largest single change to them usually happens in the last minutes.

What to do with it. Treat any figure shown before betting closes as an estimate, and check the deduction rate — it is published, it is often double a bookmaker's margin, and it is charged whatever happens.