Trading 101: William Hill Flash Odds

bashertom Announcements

Exchange Trading 101: The daily William Hill Flash Odds

William Hill release daily FLASH ODDS for horse racing at 12pm, every day, like clockwork. They take one horse and one race and BOOST their ODDS in a FLASH, with a flash lasting ten to fifteen minutes. An example is below, where Prominna was boosted from 10/3 to 5/1 in the 1735 at Lingfield on 4th October 2018.

The magnitude of the boost can vary and is typically higher than the exchange. Blindly backing each boost would provide long term profit. There are 2 drawbacks with this strategy:

  • (1) You are limited to a maximum stake,  £10 – £20 if William is feeling generous.
  • (2) Blindly backing all the boosts will see your account restricted at some point.

Therefore, there is no longevity in this strategy.

Many subscribers to matched betting take advantage of these odds – but they are not willing to ride out the variance of value betting; instead they will back at William Hill and lay on the exchange.

This strategy is fine to make occasional beer money. It is not a long term strategy.


Trading 101: Trade when you know (1) what selection in what market, (2) what direction the price will move in and (3) at what time the movement will occur.

As discussed above, we know that William Hill will boost a horse (Prominna), in a race (1535 Lingfield). We know that William Hill have a lot of customers, and we know a lot of them are matched bettors.
We have the utmost confidence that the following will happen:

These matched bettors will back at William Hill and lay on the exchange. By laying on the exchange, they will eat up all of the available lay liquidity and drive the price upwards. This will go on until after the boost finishes, then the traders and leap froggers will wait for their lays to be matched. Then the price will come down again.

Using this knowledge, we have satisfied all the constraints of TRADING 101.
(1) What market = 1535 Lingfield
(2) What direction will the market move in = the price will go up, plateau, then come back down. The plateau may last hours in quiet markets, and will last shorter times in more liquid markets.
(3) When = 12pm daily

We have two options to trade this market and make money:

(1) Lay early, let the price increase, back high.
(2) Back high, let the price come back down, lay low.

The benefits of using the exchange instead of William Hill are twofold:
(1) We can get unlimited funds on at the exchange and
(2) We do not get restricted at the exchange for using this betting strategy.

Real life case study
Promina was boosted to 5/1 when the horse was 5 on the exchange. The price quickly increased to 5.6, before plateauing, then increasing to 5.9.

Yes, there are matched bettors backing at 6 and laying at 5.9. Not so much beer money as….penny sweet money.


It is an imprecise science knowing how far the price will go;
I laid at 5.3, 5.4, 5.5 and 5.6. I traded out by backing at 5.9 and 5.8.
I then backed at 5.8 and 5.7, and laid at 5.5. I was left with the following position:



The option now existed to trade out by laying Promina by up to 362/5.6 (£64) to equalise the profit across the race – or we can underlay any amount up to £64.  We could overlay, but unless you’re a maniac then it’s a dumb option when the odds are over 3. My preference is always to have maximum exposure on one horse, so I left the profit distribution as in the screenshot above. On this race that worked out well:





  • The predicted price movements will happen most of the time, but occasionally unexpected things happen like the horse gets boosted and the price comes down. We will have to trade out for a loss. This is fine if the majority of our trades are for a profit.
  • We are not the only people using this strategy, so be patient. If the race is hours away we can let our trades sit for hours, as long as we monitor the market regularly. If the price starts drifting away then we need to make a decision to bail. One or two ticks does not represent a serious drift, this is more likely to be down to leap-frogging traders being impatient. Patience is our friend.