How to Understand Sudden Shifts in Betting Odds

Determining whether bookmakers have taken professional money on a market can be tricky. But the most obvious usually occur when betting on horses.

Often, when a horse that has started at 8/1 in the morning hardens in the market and ends up at a price nearer evens, this is a sign that that either the bookie – or professional punters – know something the casual bettor doesn't.

Race-Fixing

Notable examples of horses shortening in the market in the past have come from race-fixing. Over the years, professional con-men have entered horses in races that clearly didn’t suit. When the horse ran badly enough and became a big enough price for the next race, it would be entered into a race that did suit and the con-man would stand to win big next time out.

From a punter’s perspective, you’re trying to figure out why a significant price shift has happened. Sometimes this is due to big money being wagered by people in-the-know in examples like the above.

Form-Readers

New betting sites employ ‘form-readers’ whose job it is to read a horse's form in order to put it in a particular place in the market. 

These form-readers talk to the trainers and owners of their respective horses and gauge what kind of a chance runners have. With this information, bookmakers can price their horses accordingly. This is why you sometimes see a horse that hasn’t run for a year at the head of a market, or a horse that hasn’t finished in his last three starts suddenly halve in price, for example.

Tipsters' Influence

Some of the country’s most successful tipsters can cause markets to fluctuate all by themselves with their tips. You'll see this especially when you're looking at Cheltenham odds around the time of the Festival.

If a well-known tipster in the media tips a specific horse, you can expect public money to respond accordingly, causing a considerable swing in the market. 

Professional Money 

If a horse or dog – or football team, for that matter – shortens considerably in the market as an event is about to start, then this is can be a decent indication that professional gamblers have gotten involved. 

Bookmakers usually shorten the odds of a participant long before the occasion in order to limit their losses. So, unusual activity right before the start suggests somebody knows something the bookies don’t. That said, it is not a guarantee and the professionals sometimes get it wrong too.