Last week I wrote the first of two articles looking at price movements from Opening Show odds to SP in National Hunt racing, writes Dave Renham. This is the follow-up piece expanding on that initial research. As before, the data has been taken from the last five full years, covering 2020 to 2024. I have used William Hill bookmaker prices, and I will use ‘OS’ to denote the Opening Show odds.
To begin, I would like to look at differing race types. Specifically, I want to compare chases with hurdles to see what percentage of these runners shortened in price, lengthened in price (drifted), or stayed the same price, when comparing their OS to their SP.

As the graph indicates, there was a bigger percentage of drifters in hurdle races compared to chases, and hence fewer hurdlers shortened in price compared to chasers. If we look at non-handicap hurdle races versus handicap hurdle races it can be seen that in non-handicaps 49.4% of all runners drifted, whereas in handicaps the figure stands at 46.2%. Interestingly, this percentage ‘swing’ is reversed when we look at non-handicap chases versus handicap chases. The splits this time see more drifters in handicap chases (44.7%) compared to 41.1% for non-handicap chases. This is a good example of where we can see the importance of digging down into the long grass. We saw this in the first article when noting the differences between certain courses, in the splits for class of Race, and in how the OS odds affect the likely direction of any potential price movement.
I also looked at bumper (NH Flat) races where 47.9% of runners drifted from OS to SP compared with 38% that shortened (just 14.1% remained the same price).
Next, I would like to see there is anything material in terms of day of the week. I am going to concentrate solely on the percentage of drifters on each of the seven days my suspicion being that Saturday will have the lowest percentage, due to having stronger markets. Let’s see:

Saturday does indeed have the lowest figure which correlates with the race class and course data shared in part one last week. Saturdays tend to have better races when the day is viewed as a whole, and more of the top tier courses are in action on this day of the week, too.
In that prior piece it was noted that Cheltenham was the racecourse that had the smallest percentage of drifters out of all the courses. With the Cheltenham Festival roughly three weeks away, I thought it might be helpful to see what the splits are in terms of runners that shortened in price, lengthened in price or stayed the same price, when comparing their OS to their final Starting Price Odds at the Festival. Here they are:

This is quite a change from what we have seen so far. Horses remaining the same price from OS to SP have occurred more than either of the other groups. Horses that lengthened in price have a figure 16% lower than when looking at NH races as a whole. I had expected the percentage figure for drifters to be somewhat lower than the norm due to the strength of the Festival markets, but I had not anticipated as much as 16%. I also did not expect the 'stayed same price' group to come out clearly ahead of the others. It has made me think that maybe I write an article where I do a deeper dive into the Cheltenham Festival in terms of price movements, incorporating early morning odds moves too. More of that to come perhaps.
Time to switch attention now to some trainer data. To begin with here are the trainers with the highest percentage of runners that have shortened in price between OS and the ‘off’. To qualify a trainer must have had at least 200 runners during the period of study:

13 of the 20 trainers have higher percentages for shorteners than for drifters. When I looked at flat trainer data back in the Autumn only two trainers managed that feat. Four of the ‘big guns’ - Nicky Henderson, Paul Nicholls, Willie Mullins and Dan Skelton - are absent from the list, so what about them? Here are their splits coupled with a selection of some other familiar names not seen as yet (again the table is ordered by % of shorteners):

It is quite interesting to see Skelton, Nicholls and Henderson with the smallest percentages for horses that have shortened in price from OS to SP. It is also interesting when we compare their shorteners with their drifters in terms of value by using the A/E index. The graph below shows the splits:

For all three there has been far better value in their runners that were backed in between OS and SP compared to those that drifted. Indeed, you would have made a tiny profit to BSP on all Paul Nicholls runners that shortened in price from OS to SP.
In terms of negatives beware Henderson drifters in chases: of the 283 chasers that drifted 43 won (SR 15.2%) but they accrued losses of £58.26 (ROI -20.6%) to BSP. In addition, Henderson non-handicappers (any NH race type) that drifted have also proved to be poor value losing over 18p in the £.
As far as Paul Nicholls is concerned a drifter is a bad sign if ridden by stable jockey Harry Cobden. Although just over 20% of them have still won, backing all 834 qualifiers would have seen a loss to BSP of £184.51 (ROI -22.1%). Conversely, drifters from the Nicholls yard not ridden by Cobden have won more often (21.5%) and proved profitable to BSP to the tune of £108.80 (ROI +19.3%). These runners would secured a blind profit to Industry SP of around 6p in the £ as well. Meanwhile, if a Dan Skelton runner drifts at Cheltenham, beware, as only four of the 87 have won for losses of over 66p in the £.
My final piece of ‘drifting’ data for these three trainers comes in the form of their record in Class 1 races when this occurs. Their results are shown below:

Henderson’s record is modest but not terrible, but for the other two the figures are very poor. I would not be keen in the near future to back a Skelton or Nicholls drifter in a Class 1 event.
Sticking with these trainers and Class 1 events, let us see their performance when their runners shorten in price before the ‘off’. Unsurprisingly, we see a contrasting picture to the earlier one:

All three have edged into profit with solid figures across the board. Clearly, for these three trainers in top level races the strength of their runners in the market just prior to the off is very important.
Olly Murphy is another trainer who has a couple of stats worth mentioning. Interestingly, his drifters have won almost as often as those that have shortened in price – 18.2% versus 20.6%. Given those numbers, it won't shock to learn that his drifters made a positive return of 5p in the £ whereas his shorteners lost 20p in the £ (to BSP). Sticking with those runners that have shortened in price, when they started favourite they broke even. When they were not favourite losses have been 27p in the £.
Lastly in this piece, I want to focus on Irish maestro Willie Mullins as there are a few useful titbits when it comes to his stats. There are three powerful stats of which we ought to be aware:
1. Any Mullins drifter at the Cheltenham Festival is not a good sign. 100 horses have drifted from OS to SP at the March showpiece of which only 11 won (SR 11%) for a BSP loss of £43.36 (ROI -43.4%).
2. Don’t be lured in by bigger-priced runners from Mullins ‘being backed’. Horses that shortened in price from an OS of 18/1 or bigger are 0 from 54.
3. When one of Mullins' horses shortens in price from OS to SP take note of the jockey. The table below shows why we want Paul Townend on board:

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This article has highlighted some interesting patterns in terms of how the market moves during that brief period between the opening show and the start of the race. I think some of the trainer data for Messrs Henderson, Nicholls, Skelton, Murphy and Mullins could prove really useful and help to point us in the right direction when contemplating the timing / placing of our bets.
- DR