Wesmip1, a loss of 2.2% before commission on betting on the fave is quite remarkable but not too surprising with Betfair.

As to using the prices on BAT - I think I may have posted the following earlier but it might be worthwhile repeating. When BAT was introduced I compared the Final Trade price with that shown on BAT. I looked specifically at a fave which incidentally I layed at around $3. The Final Trade price was slightly over $3 yet BAT showed it's price at $2.20 which is a huge discrepancy.

I queried this with Betfair who informed me that BAT mirrors the Bet price on the betting screen immediately AFTER the start of a race. In my instance, the $3 was snapped up at the death which left $2.20 as the best available Bet price. BAT identified this price of $2.20 and automatically transferred it to its screen.

So, in some instances BAT is underpricing itself, and therefore with real betting the fave might even show an overall profit. Also, the Lay price would most likely be very flattering as I presume in the above instance the Lay price would be the next "click" of $2.22?

Just thought I'd mention it.

Michael.