Pinatubo is -110 with Bovada to win the 2,000 Guineas at Newmarket on Saturday. That means in a two-way book at the standard bookie profit margin, it's a pick against the field, which is also -110. Another option is to lay the favourite at -117.65 on the Betfair betting exchange, which presents an arbitrage opportunity at that price. (Please note that the market adjusts quickly, so the arb won't last long and will probably have gone when this article appears.)
Arbitrage betting involves taking advantage of odds variances in a betting market. Sports arbs are also known as ‘sure bets' because you are guaranteed to win regardless of the outcome of the event. Conditions sometimes allow you to bet on both outcomes in a two-way market because two online bookmakers have a different opinion. Alternatively, you can place a back bet with a bookmaker at a certain price and lay the same outcome (accept a bet) at a lower price on an exchange.
The flaw in arbitrage betting is that the odds will soon move to eliminate the opportunity. You must also take into account winning exchange bets commission, which can negate the small risk-free edge.
A perfect example is the temporary price discrepancy for Pinatubo to win the Guineas this weekend. Here is a guide to how you could make money by backing and laying the horse at the latest odds with a fixed-odds bookmaker and betting exchange:
• $200 back at -109.89
• $212.22 lay at -117.65
With the betting exchange taking a 5% commission, the bets above result in a -163.93 profit. While this is a tiny win, it comes with no risk and could be a money spinner if you ramp up the stakes.
The window of opportunity is small, but the arbitrage on the 2,000 Guineas has been available for some time. The other question is: if you only bet one side, do you back or lay Pinatubo?
Last season, Pinatubo earned the best rating for a juvenile horse for 25 years. The horse was much better than every other two-year-old and, on face value, looks a good bet at -110. However, any quick ground at Newmarket would count against him. Pinatubo apparently does not work well at home and improves for a run. The colt has not run for 238 days and could be more vulnerable than some of the other runners to not having had a trial before the Classic at Newmarket.
When you have a favourite that accounts for 50% of a betting market, there is often some each-way value further down the field. Fifteen horses have been declared to run, which means each-way bets with UK bookmakers are settled at one-fifth the odds for three places. Pinatubo has an Official Rating of 128, while Siskin's best mark is 115. Those numbers suggest Siskin will not beat Pinatubo, but +3300 at Bovada looks a big price.
The 2,000 Guineas betting market is all about Pinatubo. You can back the horse at a shade of odds-on or lay the horse at about the same price, which means you have 14 runners in the race. You can ignore the arbitrage and sit on the fence with Pinatubo. An alternative is a bet on Siskin to win the race or make the payout places. Personally, I can't forget that Pinatubo is head and shoulders above the field so I will be backing the horse to win the first British Classic of the season.