A steam move in betting is a price that shortens sharply and fast across most of the market at once, as money or news reaches several bookmakers and the exchange within minutes. In racing the runner is called a steamer. With illustrative prices, a runner backed from $7.00 to $4.50 in five minutes has steamed: its implied chance (1 / price) jumped from 14.3% to 22.2%.
It shows that something happened, not that the money behind it was right, and by the time you see it the old price has mostly gone.
How a steam move shows on a price history
Illustrative prices for Runner 6 at three bookmakers, with the exchange shown as the midpoint between its best back and lay prices:
| Minutes before the jump | Bookmaker A | Bookmaker B | Bookmaker C | Exchange midpoint |
|---|---|---|---|---|
| 25 | $7.00 | $7.00 | $6.50 | $7.30 |
| 15 | $7.00 | $6.80 | $6.50 | $7.10 |
| 12 | $5.50 | $5.50 | $6.50 | $5.40 |
| 10 | $4.50 | $4.50 | $6.00 | $4.55 |
| 8 | $4.40 | $4.50 | $4.60 | $4.45 |
On a fluc chart (the runner's price history) the move is a near-vertical drop from 15 to 10 minutes out, at Bookmakers A and B and the exchange together. That breadth marks steam: one bookmaker cutting alone may just be managing its own book. Bookmaker C lagged for a few minutes, then caught up.
Sport shows the same shape before a game starts: an AFL line can jump several points at most bookmakers within minutes of a late team change. Why betting odds change covers the causes.
Steam vs gradual firming
| Steam move | Gradual firming | |
|---|---|---|
| Speed | Minutes | Hours, or a whole day |
| Breadth | Most bookmakers and the exchange together | Often one bookmaker, with others following later |
| Usual trigger | News, or a burst of money the market trusts | Steady money, or an early price being corrected |
| On a fluc chart | A step down | A gentle slope |
The money behind steam is often called sharp money, though nobody outside a bookmaker sees who bet. A move against the side most bets are on has its own name, reverse line movement.
Why chasing steam is late information
Back Runner 6 at $4.50 after the move and it must win more than 1 / 4.50 = 22.2% of the time to break even, against the 14.3% the market implied at $7.00. Following steam only pays if the market still rates the runner too low, and judging that takes your own price, the core of any betting strategy.
The price that still looks long belongs to a bookmaker that has not caught up: Bookmaker C's $6.00 at 10 minutes, 6.00 / 4.55 - 1 = 31.9% above the exchange midpoint. Taking prices like that is called steam chasing, and three things work against it:
- the price is often cut before your bet is accepted;
- a bookmaker can limit or close an account that keeps taking prices it was slow to move;
- the steam can be wrong, and a steamer loses like any other runner.
Risk: Betting involves risk. After steam the price left is the short one, and a price that has not moved yet can be gone before your bet lands. See responsible gambling for limits and support.
Spotting steam on the Terminal
B337's Terminal shows Betfair back and lay next to 40+ bookmakers' prices across racing and sports, and the price history (flucs) of each price shows whether a racing move is broad or one bookmaker's.
Prices are read on a repeating cycle, not tick by tick, so a fast move can show as one step, or only after it has finished: check your bookmaker account before betting. A free account opens a limited view of the Terminal with live odds. Betfair is a trade mark of its owner, and B337 is not affiliated with it.