Slippage in betting is the difference between the price you expected to get and the price your bet was actually placed or matched at. Go to back a runner for $50 at $4.50, have the bet land at $4.20, and a winner returns 50 x 4.20 = $210 instead of 50 x 4.50 = $225: the slippage cost $15 (illustrative prices).
Slippage on an exchange, worked
On an exchange, a bet bigger than the money at the best price is matched down the ladder. Illustrative prices: you ask to back $400 at no less than $5.80, and the ladder holds $150 at $6.00, $100 at $5.90 and $250 at $5.80.
| Price | Amount matched | Profit if it wins |
|---|---|---|
| $6.00 | $150 | $750 |
| $5.90 | $100 | $490 |
| $5.80 | $150 | $720 |
| Total | $400 | $1,960 |
The average price is (150 x 6.00 + 100 x 5.90 + 150 x 5.80) / 400 = 2,360 / 400 = $5.90. At the $6.00 on screen the profit would have been 400 x 5.00 = $2,000, so the slippage cost $40. Your minimum price stops it going further: nothing is matched below $5.80, and any part that cannot be matched there waits as an offer.
Measured against the $5.80 you asked for, the $250 matched at $6.00 and $5.90 was price improvement: a better price than requested. So slippage is counted from the price you expected, and price improvement from the price you asked for.
What causes slippage
- Thin markets. When there is little money at the best price, a normal-sized bet runs through it and on down the ladder. Liquidity is the measure to check.
- Delays. Time passes between seeing a price and the bet landing: a screen that refreshes on a cycle, or a slow click. A bookmaker can also take a moment to accept a bet and come back with a lower price or a refusal.
- Moving prices. Prices move fastest close to the jump and after news, so the same delay costs more then. Methods that rely on getting in and out at set prices are the most exposed, which exchange trading strategies covers.
Lays slip too: a lay matched at a longer price than planned carries more liability for the same stake, as the lay betting guide shows.
Slippage in automated and copied bets
An automated or copied bet is placed after the price that triggered it was seen, so it can slip unless something stops it. Illustrative arithmetic, not a real tip: a tip published at $3.00 is copied at $2.85. On a $40 bet that is 40 x 1.85 = $74 profit instead of 40 x 2.00 = $80, and a price 2.85 / 3.00 - 1 = 5% worse. If the tip's edge was 4% at $3.00, that slip turns it negative.
Copy betting risks covers what else changes between a tip and your copy.
Keeping slippage in check with a price floor
A price floor is the control: below the floor the bet is skipped rather than taken at a worse price.
B337 sessions work that way: a session will not take a price below your floor or a stake above your maximum to force a bet through, and a refused attempt is listed in the dashboard. Sessions run on your own computer, which has to be on, awake, online and running B337 for a bet to go on.
Many bookmakers restrict or prohibit automated betting and third-party access in their terms, and a bookmaker can limit stakes, void bets or close an account; that risk is yours. Prices on the Terminal are read on a repeating cycle, so confirm the price in your bookmaker account before you bet.
Risk: Betting involves risk. Prices move between a signal and a bet, a floor means some bets never go on, and there is no guarantee of profit. See responsible gambling for limits and support.