Message to Betfair BDP...

[JayBee]

In a previous thread about volume problems (just before API-NG went live) you said the following...

"The below issue is being caused by rounding and currency fluctuations."

[ref - http://forum.bdp.betfair.com/showpos...5&postcount=13]

Where exactly do these rounding and currency fluctuations come from? Can you explain it in detail?

After all, I would expect the currency of a UK horse race to be in Sterling so why would there be fluctuations?

It is very annoying, especially for someone like me who creates their own candlestick charts to see a large spike caused by spurious pennies well away from the spread.

Cannot Betfair (seeing as it is supposed to be a UK company) stick to one currency and do the currency transactions elsewhere in the system? Unless of course this is some sort of tax you know what so that you can report earnings in another currency and bung The Government of Gibraltar a couple of tenners.

Data consistency is very important and having pennies appearing here and there just makes the whole system look sloppy. Having more volume than all European stock exchanges is no big deal when your accounting system is more like Billingsgate Fish Market.

I can put in a fix along the lines of 'if volume for a price updates by less than £1 then ignore' but how do I know this is not someone greening up with less than a £1 to get a perfect hedge?

You can see the problem, can you?

[betdynamics]

Is this money traded, or money available to trade?

If the latter then I could see how it MAY be affected by currency changes. For example, if someone places a 100 euro bet onto the market which is not matched, then the GBP amount available on the market at any given time is dependent upon the currency exchange for the euro.

Presumably the amount available to be traded is displayed in the local currency, so the amount displayed will be different depending on whether you are UK-based or not.

If that is the case, and assuming that most of the bets are placed from within the UK, then wouldn't the fluctuation on any euro-based account be much higher?

This is just a guess by the way and may be way off the mark.

[JayBee]

No, it's traded volume, which makes your explanation all the more odd.

And it doesn't make good sense to be fiddling with currencies during a bet. Bettors should really have their money converted to one base currency the moment they deposit it. That's how it was for me when I used to play poker in dollar denominated accounts.

Is this money traded, or money available to trade?

If the latter then I could see how it MAY be affected by currency changes. For example, if someone places a 100 euro bet onto the market which is not matched, then the GBP amount available on the market at any given time is dependent upon the currency exchange for the euro.

Presumably the amount available to be traded is displayed in the local currency, so the amount displayed will be different depending on whether you are UK-based or not.

If that is the case, and assuming that most of the bets are placed from within the UK, then wouldn't the fluctuation on any euro-based account be much higher?

This is just a guess by the way and may be way off the mark.

[betdynamics]

Yes - I can't see how it would apply to a traded volume (as the currency exchange must surely have already taken place).

[JayBee]

Yes - I can't see how it would apply to a traded volume (as the currency exchange must surely have already taken place).

Yes, I agree.

I get some enormous spikes on my candles because of this.

I know that commercially available software offerings have worked around this as I never see such spikes on their charts.

However, I think their workaround (probably ignoring small volume changes on a price) means that their charts are never a complete picture of market activity.

If anyone has an alternative solution then I am all ears.

[BetfairDeveloperProgram]

Hi JayBee,

The below issue is being caused by rounding and currency fluctuations

The issues at the time were caused by a defect and the above message was followed up with the message below:

A fix will be deployed tomorrow morning at around 9am which should stabilize things

Therefore, if this is still causing issues, please provide further details and specific examples.

There was some additional information provided regarding untracked tradedVolume updates via https://forum.bdp.betfair.com/showth...0186#post10186

We are currently investigating providing a 'market journal clock' with our listMarketBook response data. This will help developers to more accurately identify the newest version of the returned data.

Kind Regards

Neil

[JayBee]

Here are some figures from market 1.116727793 runner 7288668

They are for price 2.56, which was well above the spread being traded at the time. Therefore it is one of these so-called "rounding errors".

The last figure in the list put a spike in my chart as I had a value of 50p and below to ignore updates.

There needs to be a trap in your system that realises any increase at a price that has not been traded in the spread must be spurious. Doing so on my side would be a complete waste of CPU cycles.

Date lastMatchTime(market) - selectionId - Traded Vol Price - New Value - Old Value - Difference

15/12/2014 09:59:54 - 7288668 - 2.56 - 304.54 - 304.37 - 0.170000000000016
15/12/2014 10:00:55 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:02:00 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:02:42 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:03:02 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:04:59 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:08:01 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:08:56 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:09:52 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:10:35 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:11:52 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:12:52 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:13:40 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:15:00 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:15:53 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:16:59 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:17:51 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:19:52 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:20:59 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:22:26 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:23:50 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:24:46 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:25:52 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:26:55 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:27:54 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:28:48 - 7288668 - 2.56 - 304.65 - 304.37 - 0.279999999999973
15/12/2014 10:30:56 - 7288668 - 2.56 - 304.91 - 304.37 - 0.54000000000002

[JayBee]

No news?

In case you are about to say, "We have not been able to replicate this."

Just choose any horse today and monitor traded volume off the spread. You are bound to see fluctuations.

[BetfairDeveloperProgram]

Hi JayBee,

This has been raised with our dev team for investigation so we will update you when we have further information.

Thanks

Neil