A day at the races: lining your pocketbook.

Alexander Mitchell
4 min readMay 10, 2021


Bookies: bastards, braggarts and borderline criminals. One seldom finds a group of people so detestable. Preying indiscriminately on the elderly and the stupid, destroying families and relationships. A vice so old all Abrahamic texts reference it. A dirty habit and a tough one to break; most importantly, it is scarily commonplace. People I look up to take part; intelligent and creative people. It taps into our inner psychology, our optimism, hopefulness and our fear of poverty. A quick thrill with massive consequences, a genuine bonafide cultural phenomenon.

Like cheese, punting pairs nicely with a drink. So there’s never a lack of a drunken fiver at the TAB. Beyond comprehension are the lives this habit has ruined. Sure, it makes the game more exciting but it promotes the inner drone in all of us. Pandering to our hopes for easy money and an easier life. The irrational devil on the shoulder of all of us. Promising that we are one bet, slot-machine or lotto ticket away from financial nirvana.

One usually must be of sound mind to validate a normal contract; yet bookies make millions from transactions with a side of lager.

The way bookies make money is simple. The sum of their odds (adjustable) will usually equal about 105%. 5% being their takings. Take a recent tennis match as an example.

John Millman @ 2.33. VS Alexei Popyrin @ 1.56
(1/2.33) + (1/1.56) = 1.07, or 107%.

These odds are dynamic. So if punters bet on Millman and his odds decrease, the odds for popyrin will increase. Hold your course though; the sum always factors the bookies’ margin.

Somewhat irritating, is the fact that these odds are universally similar. If I move to PalmerBet, the margin will be the same. Same with PointsBet, Bet365, LadBrokes etc ad nauseam. What’s the point? Well, these businesses clearly communicate with each other, ensuring their odds aren’t too optimal for the layman. Surprising, isn’t it; crooked Bookies.

So, how can a spiteful punter win? A huge amount of research and some good luck doesn’t go astray. Here are a couple of lessons I’ve taken from a very obsessive month searching for arbitrage opportunities.

Lesson #1 AFL odds are too closely monitored for an opportunity.

  • Bookmakers monitor each other’s odds very closely with AFL. They’re within a fraction of each other. The only arbitrage opportunity I found was 15 minutes before a game started. I think the reason for this was a late injury. Look to other sports.

Lesson #2

  • Choose a sport that you can bet on all year.

AFL is seasonal. You can’t bet throughout the summer and that’s no fun.

Lesson #3

  • Simplify, simplify, simplify

If you are betting on a sport like soccer (or football wherever you are in the world), a draw is a very real possibility. Meaning you would have to place an extra bet; as there is a third eventuality. In games like tennis, there is one winner and one loser. Meaning a maximum of two bets. Which makes your life easier.

Fortunately for me, I found a few opportunities recently. A recent peach, was a tennis match in Cairo. Shintaro Mochizuki played Carlos Montagud. Shintaro was favourite at 1.35, with Montagud at 4.50. Only, not with the same Bookmaker.

Creating a grand total of 96.30%. An arbitrage opportunity, huzzah! I placed 1,500 on Mochizuki and 450 on the dog. Mochizuki got up comfortably. But it really doesn’t matter who wins.

The trouble is multiple fold. I know that I’ll be caught and rubbed out. As a somewhat recent ABC report pointed out: @https://www.abc.net.au/news/2019-01-20/gambling-how-bookmakers-stop-winning-betters/10708394. It’s not Illegal, but winning is to be discouraged. Because the house must always win.

When punters are locked out of these agencies, they go overseas. Risking punitive action; usually in the form of a large fine. Trouble is, nobody is lobbying against closure of profitable accounts. Because gambling is a dirty habit. To be discouraged anyhow and anyway. My philosophy is different: “If they can make good money from easy business, why shouldn’t we?”

There are also many other ways to use probability against bookies. There is the use of implied odds with horse racing, spread betting on AFL etc. But these lack the simplicity of arbitrage betting on tennis. I think it would be worth creating a bot that can be accessed via subscription. That alerts customers when there is an arbitrage opportunity in tennis. Let me know if this is something you would pay for.

Alexander Mitchell



Alexander Mitchell

Market Nerd. Interests in Real Estate, ASX, S&P & Crypto Currency