If Betfair is an exchange, then how do they come up with the prices on offer when nothing is exchanged?

An example today was a Harness race. There was $17k plus in the pool and up until a few seconds before the start when I captured the Betfair data, only 4 of the 8 horses had any money exchanged. Of those 4, 3 filled the first 3 placings.

In other words are all the prices we see simply contrived by an algorithm and don't relate to money wagered at all? This happens all the time with the Dogs, where the favourite is smashed and everyone hops on board and drives the price down. Many selections would only get a pittance or nothing wagered on them, making there implied volume as a % of total odds, look like 2,000:1. However, you're only offered 80:1.

My research backs this up as I'm doubly wary about laying any dog/ horse, apart from the favourite, in a lightly traded race. If you want to Back longshots, that's the sweet spot region. The odds you see, mean nothing IMHO, about a selection's chances and all contrived by an algorithm trying to be competitive against bookmaker opposition.

That Pinjarra race I quoted in the 'Good one boys' thread had an odds on fave didn't it?

Conspiracy theory, over & out!

Conspiracy theory ?

No
It was business as usual, a sting, happens all the time,
just don't know when though.

If you use the same formula as they use to get the 27%, and play around
with numbers, the obvious will appear.
In this case, why are the 3 runners that won, in negative value ?
It does not matter what comparative markets are used, but it seems there is a "hidden code" between the corporates.

I've seen this happen at the races a few times, one bookie will push the price up so another bookie does the same, yet on screen a plunge just occurred on the same runner, it gets pushed up to 10/1 while the deceptive favs are being bet on.
Well, it wasn't really a deception, it was a case of track conditions at the time, common sense prevailed, the outside barrier was clearer than the mud patch. Opportunity for some, make or break for others.

Puntz, I think you're posting on the wrong thread again? I was talking about this race, Yarra Valley R5. Take note Vol $ is the money exchanged on any single selection divided by the total converted to a price.

Horses 5. 10. 6. & 2. had no money wagered on them, at the time I recorded this, a few secs before the off.

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According to the information, "a harness race"

The previous thread was, "a harness race"...
so I thought ...,

My apologies.