A back is the same as a bet in favor. Betting in favor consists of placing a bet that that team, player or proposition wins that match. It is the same as we do in traditional bookmakers, so it does not present any difficulty.
For example in Barcelona – Betis:
We believe that Betis can give the bell and get a draw at the Camp Nou and we see that the back (or bet in favor) is at 11.5. If we bet € 10 in favor of it, we will be obtaining net dividends of: (11.5 * 10) -10 = € 105.
Remember that: Net dividends = (C * A) – A = A * (C-1)
From where A is the amount wagered or bet and C the available quota.
This amount will have to subtract up to 5% commission that Betfair takes from each bet won. This percentage varies from 1 to 5% depending on your activity on Betfair.
In back bets, the risk always matches the amount bet.
On the other hand we have the lay (or bet against). This is the main advantage and novelty that betfair introduces compared to the rest of the bookmakers.
Betting a lay is the same as betting against a certain player, team or proposition.
In lay bets or against risk, it never coincides with the amount bet, unless the odds are 2 or even.
We continue with Barcelona – Betis in the Copa del Rey;
We see that the quota in favor of Betis is 25 and the quota against 26 (euros per euro wagered). More than once I have been asked if betting that Betis does not win is priced at 26 euros per euro bet. Nothing is further from reality. The price is much lower since when you act as a bookmaker, you are offering the user a quota of 26, bearing the risk yourself.
If we bet 10 euros against Betis at this rate we will have a risk of 250 euros, or what is the same, we are risking 250 euros to win 10 (from which it will be necessary to deduct the 5% commission in case our bet is a winner), which doesn’t seem like a good idea.
To calculate the risk we must bear to make a lay bet we use:
Risk assumed in a lay installment: C-1
For example we have the following lay odds in Villarreal – Sevilla:
Villarreal lay 1.98, In this case the risk is 0.98 euros ours for each euro of estimated profit. In the case of betting 10 euros against Villarreal, our amount at stake or risk will be 9.8 euros.
Tie lay 3.75, In this case the risk is 2.75 euros ours for each euro of estimated profit. In the case of betting 10 euros against the tie, our amount at stake or risk will be 27.5 euros.
Sevilla lay 4.5, In this case the risk is 3.5 euros ours for each euro of estimated profit. In the case of betting 10 euros against Sevilla, our amount at stake or risk will be 35 euros.