Betfair Last Traded Price

[criptoguito]

Hi everyone. I have some questions about the betfair's historical data (football).
What exactly is the last traded price (ltp) with regard to the back and lay odds?

It's supposed to be the price at which there was a transaction.
But was it a price that was backed or a price that was laid?
Is there a way of translating ltp to the type of bet (back or lay) ?

Anorher thing I haven't figured out yet is the spread between back and lay odds. Ideally for every backer there should be a layer, each one paying each other out. So, who keeps the spread money? And what determines this spread?

Looking forward for some enlightnment.
Thanks!

[CallumPerry]

The LTP is both a back and a lay bet, it is where the two meet. It is the latest agreed price by one user who is backing and another user who is laying.

There won't be a spread because of this if you're taking a price. If you're making a price (order is one tick out from the LTP) then you will have that one tick spread slippage but not with taking a price. If you executed two bets seconds apart like this:

1) You back £2 at 4.0 and somebody else lays resulting in a match
2) You lay £2 at 4.0 and somebody else backs resulting in a match

Then you have matched money with two different people (most likely), backed £2 at 4.0 and played the same amount at the same price, resulting in £0 scratch trade. You only need to worry about commission for any positive markets. Somebody else feel free to correct me if there's something else spread-related I am failing to think of.

[criptoguito]

But let's say there's a match - team A vs. team B, where the back and lay odds for team A are 2.02 and 2.06.
If a punter backs team A, the ltp will be 2.02, otherwise if he lays team A the ltp will be 2.06. Indeed there was a matching price between a backer and a layer at each bet but when I look at betfair's historical data, the only information given is the ltp, not the type of bet (back or lay). So, there's no way of knowing if ltp was a back or lay bet, or am I missing something?

About the spread, I was actually referring to the difference between the advertised prices for backing and laying an event. In the previous example, the spread would be 2.06 - 2.02 = 0.04.
If I back and simultaneously lay team A for 1 euro, I get 1.02 - 1.06 = - 0.04 which is not zero-sum. I was just wondering what influences this spread, but I suppose liquidity must play a major role in it.


Thanks for your input.

[Anbell]

But let's say there's a match - team A vs. team B, where the back and lay odds for team A are 2.02 and 2.06.
If a punter backs team A, the ltp will be 2.02, otherwise if he lays team A the ltp will be 2.06. Indeed there was a matching price between a backer and a layer at each bet but when I look at betfair's historical data, the only information given is the ltp, not the type of bet (back or lay). So, there's no way of knowing if ltp was a back or lay bet, or am I missing something?

About the spread, I was actually referring to the difference between the advertised prices for backing and laying an event. In the previous example, the spread would be 2.06 - 2.02 = 0.04.
If I back and simultaneously lay team A for 1 euro, I get 1.02 - 1.06 = - 0.04 which is not zero-sum. I was just wondering what influences this spread, but I suppose liquidity must play a major role in it.


Thanks for your input.

The short answer is that, no, you can't tell whether a given LTP was 'back' or 'lay'

But Callum is right - every bet has both a layer and backer, so it doesnt quite make sense to think about it in these terms. You can think of it in terms of 'providing liquidity' and 'taking liquidity'. If you have unmatched bets than you are providing liquidity and if you have a bet by taking what is on offer then you are 'taking liquidity.' So when you ask whether the LTP was back or lay, you are (I think) asking 'Was the liquidity taken from the back or lay side?' And, no, you can't tell.

Re the spread, there is always a spread because there must be different prices on either side, otherwise there'd be a matched bet. Liquidity does determine the size of the spread, but nobody keeps the money: it is just the difference. (it's possible to 'make the market' in which case you can provide liquidity on either side, and if everything goes right you can earn the spread)

[criptoguito]

Thank you for your response, Anbell.

But following up on your assertion that it doesn't make sense to think about ltp in terms of back or lay bets, would you then agree with the following statement?

"If yesterday's game ltp for team A was 2.1 then I would definitely have had the opportunity to place a backing bet at odds 2.1"

[Anbell]

would you then agree with the following statement?

"If yesterday's game ltp for team A was 2.1 then I would definitely have had the opportunity to place a backing bet at odds 2.1"

No, because the spread may have been 2.08/2.1 and the LTP may have been someone taking liquidity from the 2.1.