Liquidity in betting is how much money is waiting to be matched at each price on an exchange: the offers on the ladder that a back or lay bet can be matched against right now. A liquid market has plenty of money at and near the best prices, so a normal-sized bet goes on at the price shown. A thin market has little, so its prices are easy to move and hard to trust.
What liquidity looks like on the ladder
Here is one runner's ladder in a thin market, with illustrative amounts:
| Back price | Available to back | Lay price | Available to lay |
|---|---|---|---|
| $3.20 | $35 | $3.90 | $25 |
| $3.00 | $60 | $4.20 | $40 |
| $2.80 | $20 | $4.50 | $15 |
The back side holds layers' offers and the lay side holds backers' offers, so a backer is matched against the first and a layer against the second. Money that has already traded is counted separately, as total matched. A fixed-odds bookmaker has no ladder; its nearest equivalent is how much it accepts at the price shown before part-accepting a bet or moving the price.
Why thin markets mislead
The prices sit far apart. Here the best back is $3.20 and the best lay $3.90, a wide back lay spread. The runner's chance is somewhere between 1 / 3.90 = 25.6% and 1 / 3.20 = 31.3%, a range too wide to treat as one price.
One bet moves the price. A $35 back takes all the money at $3.20, and the best back becomes $3.00. On a price board that reads as a runner firming from $3.20 to $3.00, though one punter spent $35. A bigger bet would be matched down the ladder at worse prices, which is slippage.
How liquidity builds towards the jump
Australian race markets on the exchange usually open thin and gather money as the jump gets closer. How much arrives varies a lot between meetings, races and codes, so treat an early exchange price as a rough one: it can rest on a few small offers and sit well away from where the market finishes.
To check the pattern, pick a few races and note the total matched, the money at the best back and lay, and the spread in ticks at 60, 30, 10 and 2 minutes before the jump.
What thin liquidity does to lays and BSP bets
A lay is only matched against backers' money that is already waiting. Ask to lay $50 at $3.90 on that ladder and only $25 is there: that $25 is matched at once, with a liability of 25 x (3.90 - 1) = $72.50, and the other $25 waits as an offer. It may never be taken; what happens to it at the jump depends on your setting, as unmatched bets explains.
A starting price is worked out at the jump from the starting price bets on both sides and the unmatched offers left in the market. The less money there is, the more a few orders can move that price, so a Betfair starting price struck in a thin market can land well away from the prices you saw beforehand.
A plain starting price lay is usually placed as a maximum liability, capping what you can lose but not the price; a price limit caps the price, but the lay may then go unmatched. The exchange's own rules set how its starting price is struck and how these bets work, so check them first. Bookmaker names are trade marks of their owners. B337 is not affiliated with them.
Checking a market's depth before you bet
- Count the spread in ticks. One or two ticks, with money on both sides, is a working market.
- Compare the money at the best price with your stake. If your stake is bigger, expect to be part matched or to move the price.
- Check the total matched on the runner, and how recently it traded.
- Watch whether a small bet moves the price. If a $20 trade shifts it two ticks, the price is not telling you much.
An exchange price is a reasonable fair-price reference only when this check passes, which is the argument in exchange price as fair odds. For racing, value on the Terminal is judged against Betfair's own market; that reference is an estimate, and it is only as solid as the money behind it. B337 places no bets on the exchange; the lay betting guide covers laying from the start.
Risk: Betting involves risk. A thin market can show a misleading price, a lay can sit unmatched, and a bet priced above an estimate of fair can still lose. See responsible gambling for limits and support.