Discusión: Betfair- una polémica más....

un ejemplo más retirado del soccer forum.

Well let's use a basic Tennis example.

Federer vs Murray, it's roughly a 50:50 game and we are in the break between sets (so nothing volatile is happening). Odds look like this:

Federer 1.98 - 2.00
Murray 1.96 - 2.02
Partido muy igualado, 50/50, jugadores descansando entre sets y infinito dinero en el mercado (solo para argumentar)

A mug punter tries to put in a bet to back Murray @ 1.97 for $1000. For argument's sake let's say unlimited amounts are available at the above quoted prices.

Un apostador pide un back de Murray a 1.97 con 1000€.

At the end of the 5-second countdown, the BF bot recognises that it can lay 2.0 Federer, so it matches the $1000 @ 1.97 Murray and immediately lays $985 at 2.0 Federer. Betfair bot has therefore locked in a profit of $15 whatever happens.

Despues de los 5 segundos esperando que la apuesta entre en el mercado, el bot de betfair consigue cojer esta apuesta hecha y imediatamente hace lay de 985€ de federer a 2 (al final si el apostador tuvise apostado lay a federer a 2 tendria mejor precio que el back de murray a 1.97). De este modo, el bot de betfair ha hecho 15€ sin riesgos

"What's the problem with that?", Betfair will argue. The 1.97 punter got the price he asked for and the 2.0 punter got what he asked for. Everybody's happy. Well, no.


Betfair podrá decir que no es ningun problema ya que el apostador tuvo el precio que pidió, el apostador que tenia el lay a federer tambien.Todos contentos

Let's say that 0.5 secs after the 1.97 was submitted, someone asked to lay Murray @ 1.98. Previously, this person would have got his bet matched @ 1.97. This bet will now be unmatched.

So the net result of the Betfair bot here is to profit for $15 at the direct expense of the guy trying to lay 1.98.

Vamos suponer que 0,5 segundos despues de la apuesta a 1.97 ser submetida, otro apostador hace un lay de murray a 1.98.
Antes de esto rollo, la persona tendria esta apuesta igualada a 1.97 (porque el apostador de 1.97 ha submetido su apuesta primero).
Ahora esta apuesta del lay a 1.98 quedará no igualada.

El resultado liquido del bot es ganancias de 15€ seguras a la costas del apostador que hizo el lay de 1.98

Just think how many IP markets are running every day, and how many of these $15s BF can make in each market, and you will realise just how much BF will be creaming off directly from our pockets.

Ahora solo tendreis que pensar cuantos mercados al vivo tiene betfair durante el dia, y cuantos "15€" iran hacer con esto.

This is absolutely scandalous and I'm fairly confident we can put a stop to it once we find someone in the Gambling Commission with a brain and some ears.


Además, digo yo, betfair podrá ahora salir con ganancias duplas.
Imaginen que al final gana murray.

No solo ellos han asegurando esos 15€, como tambien iran a cobrar las comisiones sobre las ganancias del apostador que hizo el back a 1.97 de murray.

Pues si, releyendo el foro laas diferencias se las queda betfair quedando de la siguiente manera.

Jugador A: Le lanzas un back a 1.8
Jugador B: Según está llegando tu apuesta al jugador A, aparece la de otro apostante backeando @ 2 al B.

Cuando tu apuesta llega tras los 5 segundos, aunque no hubiese dinero a 1.8, betfair te lo iguala instantaneamente con el @ 2 pero dandote el 1.8 que pediste y embolsandose la diferencia del @ 2. (0.2 décimas, 20% del dinero, 20 euros por cada 100)

A mucha gente le dará igual, a otros tantos les joderá vivos su manera de apostar.

Ahora el mercado es eficiente al 100%, jamás volverá a haber arbs.

Betfair change their bet matching engine

Hardly anybody noticed but on the 18th February Betfair had changed their bet matching engine. A few tests and a look at some data confirmed immediately that something had changed.
Typically in most markets, especially in play, the market wobbles around a lot. Suddenly this stopped happening. Having armed myself with a fair bit of data I picked up the phone and called Betfair. Within a short amount of time I had an answer; Betfair had changed their bet matching engine.
Basically Betfair have made the code that matches customer bets more efficient.
Previously Betfair would only attempt to match customer bet requests against unmatched bets of the opposing bet type (backs vs. lays) on the same runner in the same market.
Now, where there is no opposing bet to match on the same selection, rather than just leaving a customer's bet request unmatched, bet matching will now attempt to match the bet request against unmatched bets on other runners. For example; in a soccer match odds market, if there is no unmatched lay bet on the home team against which to match a customer's back bet request, the bet matching algorithm will now attempt to match that request against back bets on the away team and the draw. As before the process matches opposing customer bets and will not result in Betfair having a position in the market.
The net effect of this change is that customer bet requests will stand a greater chance of being matched and the markets will be correspondingly more efficient. Betfair are gradually rolling this out across all applicable markets on Betfair while looking to ensure that there is no deterioration in bet matching performance.
How will this affect your trading? The fact that I didn’t notice it immediately may tell you something about how it affected my trading. But I guess it may affect some people depending on what your strategy is. For people who have relied on in-efficient markets this is obviously a bit of a blow and I expect quite a bit of fall out from people who have relied on this strategy. The more general implications are difficult to assess, but if you are doing conventional trading then you will be general asking or taking prices and I can’t see how things change immediately but I’ll obviously keep an eye on things. After talking to Betfair they have prepared a Q&A which they agreed I could send out to Bet Angel customers. This should answer some questions on this change.

New Bet matching engine : Q&A sheet

Q. Are Betfair now “active” in our markets/are we running a bot?
A. What we’ve changed is a core part of bet matching. When we get a bet request we’re now looking at all the customer bet requests it could be matched against, not just opposing bets on the same selection. It would be misleading to describe that as being a bot, or Betfair being “active” on our markets, as matching customer bets is what Betfair does. Betfair is not taking a position in the market as a result of this change.

Q. Why the change / why hasn’t Betfair done this before?
A. Betfair has done this before. In the early days of the exchange bets were matched across selections rather than remaining unmatched. The only reason for retiring that functionality was technical – it had a negative impact on performance because the process that matched bets was much less efficient than now. Now that we have a technical solution we’re implementing it.

Q. Does this change raise any regulatory issues?
A. As a matter of course Betfair highlights any changes to the code base or operations to the relevant regulator, in this case The Gambling Commission. Before any change was made Betfair approached the GC and explained the proposed changes in detail.

Q. Why is this not happening on all markets all the time?
A. Our first objective is not to cause any impact on bet matching performance, so the enhanced matching code is being rolled out gradually across our markets.

Q. How does this affect the in-play delay/is someone bypassing the in-play delay?
A. The new process works in exactly the same way as the old process: bets placed that are subject to the in-play delay are queued for the appropriate time, then their status changes to “available to be matched”. Only at this point does the matching process look to see if there are other unmatched customer bets to match against. While Betfair will now look for a greater range of possible customer bets to match against, the order and timing in which this is done remains unchanged. There is no selective matching taking
place. Matching only occurs if there are opposing customer bet requests.

Q. If a bet is matched by this new process why is the bet request never visible to other customers in the market view?
A. If a customer places a back bet that matches an available lay bet on the same selection,that back bet request isn’t displayed in the market view. Only bets that are unmatched aredisplayed in the market view as offers to other customers. This remains unchanged forbets matched across selections.

Q. If I request a price do I still get “best execution”?
A. Yes. The part of the matching process that matches backs against lays remains unchanged: If your bet would have been matched at better odds before it will be matched at those same better odds now. It’s only if there are no opposing bet requests on the same selection to match against that we will attempt to match your bet against bets on other selections. In that case we currently have no way of providing a price improvement above
the price requested. Importantly:

1. This isn’t a change – you don’t get best execution across selections now. If you attempt to back a tennis player at 1.9 when his opponent is available to lay at 2.0 then 1.9 is the best price you can be matched at, and your bet could remain unmatched. You wouldn’t have been matched at the theoretically best available price of 2.0 (derived from bets on other selections) previously, and we haven’t introduced that improvement yet in this latest change.

2. The limitation to any change we make to bet matching is performance. It would be unacceptable to customers for bet matching performance to deteriorate, and calculating the best price a customer could have been matched at is computationally more expensive than just using the requested price. We are however working on doing exactly that. There is no guarantee that a fast enough method exists to perform this calculation, but if it does we would expect to have this in place within the next few weeks.

Q. If Betfair could match my back bet against another customer’s lay bet, or by matching back bets across runners what happens?
A. Bets are matched first by considering opposing customer bets (backs vs. lays). The process only matches across selections when no available matching bet exists on the same selection.

Q. If Betfair can match across selections why aren’t those prices displayed in the market view?

A. We believe that if a customer sees a price on the screen and they place a bet to match it they will expect to be matched at that price even if they request a worse price. We therefore expect to display prices that could be matched across selections once we have an efficient way of providing best execution across selections.