Exposure on Betfair means the most you can lose in one market once every bet you hold in it is counted together, backs and lays alike. The exchange holds that amount out of your available-to-bet balance until the market settles, so exposure is both a risk figure and money tied up.
How exposure is worked out
Take one market, list every result it can have, and add up what each of your bets pays or costs in that result. The worst total is your exposure in that market, and if no result costs you money, it is zero. Commission does not change it: commission is only charged on net winnings in a market, and the worst result is a loss.
Two bets in one race, worked
Illustrative prices, not a real race. In a 10-runner race you back Runner 3 for $30 at $5.00, which makes 30 x (5.00 - 1) = $120 profit if Runner 3 wins. You also lay Runner 7 for $25 at $4.00, so the lay's liability is 25 x (4.00 - 1) = $75.
| Result | Back Runner 3 | Lay Runner 7 | Market total |
|---|---|---|---|
| Runner 3 wins | +$120 | +$25 | +$145 |
| Runner 7 wins | -$30 | -$75 | -$105 |
| Any other runner wins | -$30 | +$25 | -$5 |
The worst row is Runner 7 winning, so the exposure is $105: more than the lay's $75 liability, because the back loses in that result too.
A bet that lowers exposure
Bets on the same runner offset each other. Back Runner 3 for $30 at $5.00 on its own and your exposure is the $30 stake. If the price shortens and you lay Runner 3 for $20 at $4.00, the market reads: Runner 3 wins, 120 - 60 = +$60; Runner 3 loses, -30 + 20 = -$10. Exposure falls from $30 to $10 once the lay is matched, although you added a bet.
Laying enough to make every result equal is greening up, set out in how to green up.
Market exposure and account exposure
Market exposure is the worst case in one market. Your account's exposure is the sum across every market you have bets in, and separate markets never offset each other: a race's win market and its place market are two markets, even on the same runner.
| Liability | Market exposure | Account exposure | |
|---|---|---|---|
| Covers | One lay bet | Every bet you hold in one market | Every open market |
| Worked out as | lay stake x (lay odds - 1) | The worst result across that market | The sum of each market's exposure |
| Can a new bet reduce it? | No | Yes, once matched, if every result then ends above the old worst | Only through a market's own exposure |
Funds are also set aside for unmatched offers, because they could be matched at any moment. How an exchange holds funds, splits markets and charges commission is set by its own terms, so check them. Bookmaker names are trade marks of their owners. B337 is not affiliated with them.
Exposure limits
An exchange can cap the total exposure an account may carry. If yours has an exposure limit, a bet that would take you past it is refused until other markets settle or the limit changes. Your exchange account and its terms give the figure.
With an illustrative $500 limit and $420 at risk in other markets, a new lay carrying $100 of liability is refused (420 + 100 = $520), but one carrying $70 fits (420 + 70 = $490).
A deposit limit is a different tool. Under the National Consumer Protection Framework for online wagering, Australian online wagering providers must offer deposit limits (measure 6). A request to lower one applies immediately, and a request to raise one is not applied until 7 days after it is received, as deposit limits explained sets out. A deposit limit caps the new money that reaches an account; an exposure limit caps what is at risk at one time.
Where exposure matters in practice
Before adding a bet, check what it does to every result in the market, not just what the new bet risks on its own. Using a second bet to cut the worst case on purpose is covered in hedging bets, and lay betting covers how exchange bets fit together.
B337 places no back or lay bets on the exchange, so your exchange exposure comes only from bets you place yourself. The Terminal shows Betfair columns beside 40+ bookmakers, so you can compare prices before placing a hedge.
Risk: Betting involves risk. Exposure climbs quickly when lays and backs stack up in one market, a hedge can go unmatched, and there is no guarantee of profit. See responsible gambling for limits and support.