A few weeks back I wrote an article, which you can read here, that featured an introduction to patterns of price movement from Opening Show odds (OS) to SP odds, writes Dave Renham. In this piece I want to revisit the topic and expand my research. I have taken data from 2021 to 2024 (up to and including September 21st) for UK flat and all-weather racing and I have used William Hill odds as representative of the general bookmaker community.

As I mentioned in my earlier piece, the OS 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 wagered in that period before the race starts, the odds will fluctuate. Some will shorten, some will drift, and some will either not move or end up back at the same price they started.

Price Movement: All Runners

I will begin by sharing the figures for all UK flat/all-weather runners during the study period to see what percentage of these runners shortened in price, lengthened in price, or stayed the same price when comparing their OS to their final Starting Price (SP). There is an extra chunk of data compared to the original article here, but the splits are virtually identical (within 0.2%):

 

 

We can use these figures as our baseline when comparing different angles. As can be seen, nearly half of all runners lengthen in price from OS to SP, compared with just under a third that shorten. Around one fifth of all runners end up having the same SP as their OS price.

Original Article Summary

Before moving on let me quickly recap the other main findings from the original article:

1. Horses that shorten in price win roughly 1.7 times more often than horses that lengthen in price.

2. Horses that lengthened in price when their OS was 7.0 (6/1) or less, lost only 1.5% to BSP.

3. Horses with an OS starting point of 18/1 or bigger have lengthened or drifted in price more than half of the time.

4. Horses with an OS of between 100/30 and 13/2 have similar percentages when it comes to shorteners and drifters. All other prices see a big differential as shown in the overall figures (see graph above).

5. The five trainers with the highest win strike rates of the period, namely Charlie Appleby, John & Thady Gosden, William Haggas, Saeed bin Suroor and Roger Varian combined to make a BSP Return on Investment of 5.5% when combining all of their horses that shortened in price from OS to SP.

---------------

 

Clearly if we can improve our chances of predicting the price movements of horses we are planning to back in the time between OS and the start of the race, then it has the potential to improve our bottom line.

Price Movement by Trainer

My first port of call in this piece is to examine more trainers in detail.

Positive Price Movement by Trainer

To begin with here are the trainers with the highest percentage of runners that have shortened in price between OS and SP:

 

 

The top 20 are listed and Jane Chapple-Hyam heads the list. She is one of only two trainers who had more horses that have shortened in price than lengthened, John Gallagher being the other. Focusing on her runners with an opening show price of 9/1 or shorter we get the following splits:

 

 

Over 45% of her shorter priced runners hardened in price in the 10-15 minutes before the start of the race. Compare this to the average figure for all trainers with this price stipulation which stands at 37%. That is a noteworthy differential but John Gallagher’s splits see more than 50% of his runners priced at single figures on the opening show shortening in price. His stats are thus:

 

What is quite bizarre, however, is that the Gallagher runners that drifted in price won more often than those which shortened. Not only that, but the drifters made a tidy BSP return of over 30p in the £; his horses priced 9/1 or less on the opening show that shortened to SP showed a huge loss of 44p in the £ at exchange prices.

All of the other 19 trainers in the above list had the reverse with their shorteners winning more often than their drifters, which is the pattern one might expect based on the overall data. Jane Chapple-Hyam’s performance fitted this far more typical profile, and the results of her shorteners were much more impressive than for those that drifted as the table below shows:

 

 

Chapple-Hyam’s horses that shortened also made a small profit to Industry SP. It should be noted that her 159 runners whose price remained the same also made a profit to BSP.

Negative Price Movement by Trainer

Time to look now at those trainers whose horses have drifted / lengthened the most in percentage terms from OS to SP.

 

 

As you might expect, most of the trainers on the list are lesser name trainers whose horses tend to operate at the lower end of the ability spectrum. This is reflected in a tendency to saddle bigger priced runners which we know from previous research means they are more inclined to drift than mid- to shorter range priced runners.

There are a couple of additional stats I’d like to share. Firstly, Grace Harris when sending her horses at Wolverhampton has seen 66 of the 99 runners lengthen in price, exactly two-thirds. Secondly, Linda Perratt runs more horses at Ayr than at any other track, but her runners drift in price more often than her average: just under 61% of her Ayr runners drifted in price from OS to SP, and of these 133 runners just five won, showing significant losses. At Hamilton, where Perratt also runs a good proportion of her horses, she sees a similar percentage, 64.3%, drift from OS to SP.

Before moving on from this table of trainers, it is quite a surprise to see George Boughey in this group. It is also interesting to note that his shorter priced runners have similar percentages to his overall ones. Below, there is a graph that shows the percentage splits for runners that were 5/1 or shorter at OS:

 

 

Using this OS price stipulation across all trainers sees 43% of runners drift in price. Boughey’s figure is over 10% above this. So why do so many of Boughey’s shorter priced runners drift in price from OS? That is the 66 million-dollar question, I guess; most likely is that they are frequently over-bet earlier in the day, which leads to a correction 'on the show'.

Why Do Horses Drift?

In fact, now is perhaps a good time to discuss some of the reasons why a horse may lengthen in price in the period close to the ‘off’. Firstly, it is partly due to the bookmaker’s overround being slightly bigger on OS compared with the final market overround, in order to defend against a horse which might have been offered at the wrong price - a rick, in the parlance.

Secondly, how a horse behaves before its race can influence the price, normally in an outward direction. For example, horses that sweat up in the paddock or behind the stalls are noted and this tends to be a negative which often pushes the price out. Also, some horses get very agitated in the parade ring and that warning sign tends to see the price start to drift also. Other horses get to the start fine but then become a problem, usually making it difficult for the handlers to load them in the starting stalls. Another factor can be that a horse is difficult to restraint when going to post,  expending too much energy before the start. And yet another reason for horses drifting is when a different horse in the same race is well backed. In that scenario and in order to balance the market, bookmakers will ensure that at least one horse, often more, move out in price to compensate.

Why Do Horses Steam?

Horses that are being backed close to the off can be down to a mix of reasons also. One obvious reason is because the owner and/or stable are expecting a very big run from their charge. Another reason for contracting price movements is when a horse is shortened deliberately by the bookmakers because they have 'running on' liabilities from multiple bets should the horse win. A third reason could be paddock demeanour - fitness, behaviour, physical well being and the like. And there will be a few times when it is simply not easy to explain a late market move be it positive or negative.

Price Movement by Owner

I want now to look at a selection of owners and consider the percentage splits for those whose horses have run the most during the study period. I have ordered them by the highest percentage of horses that have shortened in price:

 

 

There is a huge difference between Marc Chan at the top and Antony Brittain at the bottom. Chan’s runners do very well when they shorten in price, hitting a strike rate of 29% and producing a profit to SP of £38.77 (ROI +56.2%) and to BSP of £48.65 (ROI +70.5%).

Horses from the Shadwell ownership have also made sound profits when concentrating on their runners that have shortened from OS to SP. Of the 437 such runners 116 have won (SR 26.5%) for a profit to SP of £48.29 (ROI +11.1%). To BSP this improve to profits of £89.39 (ROI +20.5%).

One of the most interesting findings from my point of view is that Godophin’s runners are not that strong in the market. Personally I would be betting a Godolphin runner as late as possible or at BSP if fancying one of them.

Price Movement by Horse Gender

I want to look next at the sex of the horse to see if that makes a difference to the how the price changes from OS to SP. You hear comments especially about younger male horses such as ‘he is acting very coltish’, etc. Hence, I thought it was worth looking at the figures for colts, geldings, fillies and mares.

 

 

There are some differences here with fillies drifting in price more than the other three – over 50% of all fillies have drifted in price. Is this partly down to their behaviour / composure in the paddock, going down to post and behind the starting stalls? I’m not an expert in animal behaviour so I cannot say, but it definitely gives food for thought.

Price Movement in Selected Horses

Finally let us look at some individual horses – I have chosen to share the data for just over 50 horses currently in training. The ones in green are horses that are often backed and hence tend to shorten more from OS to SP; those in red tend to lengthen in price most of the time. The number of qualifying runs in 2021-2024 must have been 30+ to make the list:

 

 

Given how frequently these horses run it is no surprise that there are familiar names in the list including sprinter Summerghand. It may be interesting to note that he is rarely backed late and has drifted from opening show to starting price in nearly 60% of his races. My personal plan is to dig deeper into each horse in the table to see if I can find logical reasons why their stats are as they are. What those are could be down to one key factor, or a group of factors; it might be horse behaviour pre-race, or linked to trainers or owners, or perhaps due to the price range the horse goes off at. I think there are likely to be reasons why the stats for each horse are as they are because they are all far from the ‘norm’ at either end of the % splits spectrum.

That's all for this second helping of price movement from opening show to the off. I hope it has given you some further insights into how the market may shape up in those last few minutes before the start of the race.

- DR