Price Movement from Opening Show

In my previous article - which can be read here - I looked at favourites and specifically their Early Morning Odds compared to their Starting Price, writes Dave Renham. In this piece I am drilling into patterns of price movement from opening show to SP. This considers all runners, not just favourites. Data has been taken from the three full years from 2021 to 2023 for UK flat and all-weather racing and I have used William Hill bookmaker data.

The opening show for most races occurs around 10-15 minutes before the race is due to start. Each horse will have its opening price and then, as money is bet during the time before the race starts, the prices will fluctuate. Here are two randomly selected examples from Friday 26th July showing how prices can move. The first race was the 3.00 at Ascot which was a 10-runner handicap over seven furlongs. The prices in red were the opening show odds, and the table shows how the odds changed (moving from left to right).

In that race, four horses lengthened in price from opening show to SP, five shortened in price, and one stayed the same. The winner, Billy Mill, drifted from an opening show of 9.0 (8/1) to a final SP of 13.0 (12/1). The second race was earlier on the same day at Thirsk at 2.00. This was a 9-runner Novice contest also over 7f:

The market looks less lively than the Ascot one and this time five horses lengthened in price, two shortened, while two remained the same. Angel Express remained the same price (17.0) for the whole time, while the winner Ryka drifted slightly from an opening price of 4.0 (3/1) to an SP of 4.33 (100/30). The favourite, Tutu Star, was a positive in the market and shortened a point from 5.0 (4/1) to 4.0 (3/1) but finished only sixth.

It is time now to look at ALL runners over this three-year period to see what percentage shortened in price, lengthened/drifted in price, or stayed the same price when comparing their opening show to their final Starting Price odds. Here are the findings:

As can be seen, nearly half of the runners drifted or lengthened in price. I am not surprised by this as traditionally bookmakers used to give themselves a bigger margin when publishing their opening show. I am not sure whether the increasing influence of Betfair has impacted this dynamic, as I do not have data pre-Betfair. Let me now share the turf flat versus all-weather price change percentages before moving on:

These figures indicate that on the sand a slightly higher proportion of runners drift in price from opening show to SP when compared to the turf flat. I am not sure why this is the case, possibly due to risk aversion related to a higher number of lower grade races, but it is a stat worth taking note of. I did look at the individual course breakdown and in general the figures were similar. However, Ascot was slightly out of kilter with the percentage of horses that drifted/lengthened in price, at 41.6%. It is also interesting to note that the five courses with the lowest ‘drift’ percentages were Grade 1 courses – Ascot, Epsom, Goodwood, Newmarket and York. Perhaps the better courses have more accurate - or confident - opening shows? That would make sense given the generally larger volumes of turnover on the early prices (i.e. before the opening show).

Market movement during this short period before the start of arace is a good indicator of ‘chance of winning’ as the graph below shows when we examine the win strike rates of the three groups:

Although horses that shorten in price win more often, if we look at Betfair SP returns it is the ‘stayed the same’ group that have edged it by a couple of pence in the £. They have lost 4p in the £, those that shortened have lost 6p and the drifters lost 7p. It always amazes me how efficient a racing betting market is.

As mentioned in the previous paragraph those runners whose price lengthened or drifted have lost 7p in the £. However, if we restrict drifters to those whose opening odds were 7.0 (6/1) or less we get the following figures:

This is getting close to breaking even – losses of just 1.5 pence for every £1 bet. Using the same price considerations for horses that have shortened in price they won more often (25% of the time) but losses were still over 5p in the £.

Going back to drifters, when their opening show is 15.0 (14/1) or bigger, they have produced much greater losses at more than 11p in the £. Hence, all things being considered, horses that go out in price from an opening show of 7.0 (6/1) or less have offered the best value.

My focus now is to look at price movement from opening show to SP within different price bands. The figures are split by percentage of qualifying runners:

These price bands are based on big sample sizes so we can be confident that the general principles will be replicated in future. Possibly the most eye-catching numbers are those for bigger priced runners. Once we get to an opening show of 18/1 or more, over 50% of these runners will drift in price. There also seems to be difference to the overall ‘norm’ when it comes to those priced up between 100/30 to 13/2. The percentages between shorteners and drifters are close to parity. To see this more clearly let me graph the comparison:

The graph clearly shows this ‘close to parity’ situation with the 100/30 to 13/2 opening odds price bands. Either side of that, drifters occur more frequently than shorteners and in many cases the difference is significant. For punters this type of information should be really useful – having the overall stats gave us a good ‘feel’ but breaking it down into price bands has given us much more knowledge and understanding of how certain prices may change in that pre-race period.

Now of course, a good proportion of punters back horses on the exchanges rather than with traditional bookmakers. However, if you are still someone who bets with the bookies the info shared should help your decision making about when to place your bet. This is especially true if you tend to bet close to the ‘off’ and/or at Starting Price. Even if you only bet on the Exchanges, the price movements for traditional odds and Exchange odds tend to mirror each other, so this data should serve either way and help to inform your timing of bets. The best strategy for placing a bet at most price points seems to be to wait for SP / BSP because your horse is more likely to drift late on. With instances of opening show odds of between 100/30 and 13/2 though, it is far less clear-cut in terms of the best time to place that bet.

The last area I want to take a quick look at is trainers. I thought it may be a good idea to group the data for the top five trainers in terms of win strike rate over this three-year period. The qualifying trainers are Charlie Appleby, John and Thady Gosden, William Haggas, Saeed bin Suroor and Roger Varian. Firstly a look at the splits in terms of what percentage of these trainers’ runners have shortened in price, lengthened in price, or stayed the same price when comparing their opening show to their final Starting Price odds.

These combined figures see a difference in percentages between the two main groups of just 7%, compared with a 15%+ difference in the 'all trainers/runners' graph earlier in the piece. Logic suggests that this would have been the case – runners for more successful trainers are likely to be ‘stronger’ in the market than the norm. But it is good to see it in black and white (or green and orange!)

What is even more interesting is when we combine the results of these five trainers. Here are the findings:

Horses that have been strong in the market for these five trainers have combined to produce a fair profit. Indeed, four of the five trainers made an individual profit with their runners that shortened in price from opening show to SP – the Gosden stable was the only one to make a loss.

To conclude, understanding how a betting market may evolve from opening show to SP is an area that is rarely analysed. I have found it enlightening doing the research and some of the findings in this article should provide punters, as well as myself, with a better feel of how a market may develop on the show.

- DR

Other Recent Posts by This Author:

• More on Price Movement from Opening Show
• A Study of Owners in UK Flat Racing, Part 2
• A Study of Owners in UK Flat Racing, Part 1
• Seeking Value with Female Flat Jockeys
• Early Odds to Opening Odds to Starting Price