Author Topic: New Trigger - The Bookmaker  (Read 955 times)

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New Trigger - The Bookmaker
« on: 11 Dec 2018, 05:53 »
Dear Oxa and the trigger community,

I have developed a new trigger which imitates being a bookmaker.  I have been working on this for a while.

I have used it with real money and it works well.  There are plenty of options for users to try out to improve its performance and profitability.

Oxa - please message me.  I will send you the trigger and explanatory notes for you to review.

David Gilbertson

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Re: New Trigger - The Bookmaker
« Reply #1 on: 11 Dec 2018, 12:45 »
Hi David,

I PM'ed you.
Always try your triggers in Test Mode before switching to real money!

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Re: New Trigger - The Bookmaker
« Reply #2 on: 12 Dec 2018, 01:08 »
Oxa, I have sent you the trigger and the explanatory notes. 

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Re: New Trigger - The Bookmaker
« Reply #3 on: 14 Dec 2018, 23:02 »
Attached is the trigger and below are the notes.

The Bookmaker
 
Overview
This trigger imitates the operations of a bookmaker.
 
It makes a lay book with an over-round set at a discount to the back prices. The underlying theory is that on balance, pre-off price movements are not informative. That is, in the long run, just because a horse’s back price shortens, that doesn’t mean that the horse’s probability of winning has improved. The price movements are random in other words. Sometimes steamers are based in informed knowledge; sometimes they are not.
 
There are some basic concepts that are employed. Firstly, the book is set at a 10% discount to the back price for the favourite, and further below the back prices for the other runners. Deep discounts are sought for laying the long shots. This creates a starting book with a generous over-round, ie the starting lay book percentage is over 110%. The precise starting percentage can change from race to race, depending on the number of runners.
 
Secondly, the exposure on the runners is the same regardless of the price. If a long shot wins, the payout on that horse is the same as if the favourite wins. However, in that scenario, the lay bets won on the shorter priced runners more than compensate for the liability.
 
Thirdly, once at least one lay bet is matched, the unmatched bets are adjusted upwards at regular intervals. This is in order to attempt to balance the book. The prices are adjusted only so long as the book continues to be over 110%. All unmatched bets are cancelled once the market turns in-play.
 
That is because in-play price movements are more likely to be informative.
 
There is a separate trigger which regularly calculates the lay book percentage of the matched and unmatched lay bets.
 
The total exposure on each race depends on the market volume of that race.
 
Here are the details:
 
Lay prices
Subject to certain efficient market conditions, at 5 minutes before the start of the race, the trigger lays the favourite at a 10% discount to its back price. It lays the rest at a larger % discount to their back prices. The discount is up to 70*runner_number/25 for the outsider.
 
So if there are 5 runners, the outsider is layed at 70*5/25 + 10 % discount to its back price, ie 24%. With 25 runners, the discount for the outsider will be 80%.
 
The discount range is linear from the favourite to the outsider.
 
Exposure
The formula is:
MINV(market_volume/100,100).
 
The minimum value function is used for two reasons. Firstly, so large bets are not placed in a market with low volume. Secondly (and paradoxically), to set the maximum exposure per race. It means that the most that the exposure will be is the smaller of 100 and market_volume/100.
 
Naturally, these figures can be altered.
 
Attempting to balance the market
Once at least one horse has been layed, the lay prices of the rest of the runners are increased by 2 ticks every 6 seconds. The idea is to try to balance the book by increasing the lay prices for the unmatched lay bets. There is a corresponding reduction in the lay amount in order to keep exposure unchanged.
 
Once the book percentage of the bets (ie the total book percentage of the matched and unmatched lay bets) drops below 110%, the prices will stop adjusting.
 
Greening up
There are optional green-up triggers. They are disabled in this version.
 
Monitoring
The market monitoring should be set at at least 5 minutes before the off. The idle refresh rate should be set at 3 seconds.

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Re: New Trigger - The Bookmaker
« Reply #4 on: 15 Dec 2018, 03:50 »
What a brilliant piece of coding.
Congrats and thanks.

 

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