Lay bets matched higher than requested price

Never seen that - I'd screenprint the My Bets item that showed the requested odds and actual odds and get onto the Helpdesk. 

I know it's possible to get a sitution that looks like the inverse has happened for back bets (bet matched shorter than requestd) but that's just because the unmatched bet has bee reduction factored down and the My Bets pages show the price you originally asked for (before RF)  and the price actually matched (after RF, which will be lower).

I can't see any valid way to get what you're seeing with lay bets.

I haven't experienced this but I did notice last week I put a lay order in - can't remember if it was horse racing or football - and the next price matched was below my requested price yet I didn't get a penny matched myself. It wasn't as if my money was still counting down either, it was most definitely waiting to be matched.

Thanks Longbridge - I can't see a valid reason either.  But if it were a common problem then other people would be seeing it - and I'm sure we'd have heard about it.  I reckon it's happening about every 100 bets for me.

Interesting Darlo - I wonder how that can happen.

This is pretty serious if this is happening.  Are you 2 using the betfair website to place your bets or a 3rd party/own software through the old/new api?

I ask because I know the "new" website has caching issues in terms of the presented data when you're not logged in (maybe the odd hiccup also when you are logged in?), I wonder if it is something to do with that?

(If betfair are front running then that is really serious, would undermine everything)... must admit this had been a worry of mine, since the introduction of the sportsbook... i.e., conflict of interest) 

I hope this is just anecdotal, to do with website caching issues?

Mine was through API software - Geeks Toy. The only explanation I could come up with was that although it appeared my money was waiting to be matched and then money jumped over me, the money that was matched didn't appear on my software for several seconds. I wasn't bothered in the slightest and had almost forgotten about it until I saw this thread.

I had it today, the two prices in front of me did not get matched yet mine did, it seems like the prices sometimes disappear for a split second then come back?

I remember from quite a few years back there were bots here that were spoofing the markets.  Through the old api they would send a bet request and a cancel request at the same time.  If this was done quickly enough and often enough, the bets would appear on the screen (through the caching mechanism) even though they couldn't be matched.  From memory, BF put in a fix to prevent this.  Now betfair have a new api, maybe this is happening again, and explains what you wrote trebor?  I believe this kind of activity (spoofing) is illegal in financial markets, not sure about sports betting?

Queue jumping though, or being matched at a disadvantageous/erroneous price, is a major worry if the above is true?  It could just be an issue with Geeks toy as everyone has to move over to the new api by November, when the old version is switched off (why I was asking about 3rd party/api usage).

What sort of stakes are we talking about? 

Technically I have just experienced this whilst setting up my Live Video 'freeview' bets for this afternoon's racing.  Laid 3.55, backed back at 3.55 (not self-matched and bets placed in that order) and showing a potential loss of 1p on that horse.  How can that be?

This is all interesting.  Something else I've spotted - some bets definitely take longer to match than others.  So in experiments I can fire 2 bets in quick succession at the same price, and although the bet IDs are in the right sequence, they are reported back to me out of sequence, i.e. the first bet comes back as matched some time after the second bet, and the fact that the second bet comes back first by quite a margin indicates it can't be a comms problem.

The golf markets matching algorithm is most definitely broken.

Here's an example of a single bet of £70.05 @ 2.22 matched in various portions in the following sequence:

£2.00 @ 2.00
£13.00 @ 1.8
£34.05 @ 2.22
£8.00 @ 2.22
£13.00 @1.8

I get how the first part of the bet can be matched at below 2.22.  The bit I don't get is how come the last part of the bet is matched at 1.8.  The last 1.8 must have arrived after my 2.22, if not why wasn't it matched before the 2.22?

I'm probably missing something - can someone explain?

Ryder Cup markets definitely broken for me - think it's something to do with crossmatching bot. If I don't ask for the exact price that is available I don't get matched even though there's better prices available.

Nothing appears to be broken in the Ryder Cup markets but cross matching is currently switched off in those markets.

No cross matching algorithm prices are generated on the web interface. Virtual (cross matching) prices will continue to be displayed if you have the option 'show virtual prices' switched on in your software.

I'm regularly seeing momentary overbroke or underbroke books, one match in particular Steven Gallagher-Phil Mickelson, but also whenever an individual match takes a turn.

Some of it also because of huge gaps in the market, for example G-Mc just matched at 1.10 while tie matched at 5.5.

Momentarily over-round books are almost inevitable in any reasonable liquidity volatile in-running markets in which cross matching is switched off. No accumulation of over-round bots subject to the in-play delay can possibly achieve what Betfair's x-matching algorithm can do without the delay.

It's not that unusual to see cross matching switched off in selected markets whilst it continues to operate in other markets. Often, in in-play markets in which x-matching is off, you can beat the automated over-round bots using software with manual input.