Last Friday I noticed that favourites (I only looked at races where the Betfair fave was under $3 and it was the pronounced fave) that almost immediately after the race-start that their Lay price on the Exchange was surprisingly less than their S.P. price.

However, if their Lay price was more than their S.P. price then they more often than not firmed during the race (in-running) to be under their S.P. price. And the few that did not firm did not win the race.

Yesterday I was not at my computer for a long time, but before the race I bet S.P. for $5 and then layed it on the Exchange for $6 for two of these races.

I ended up with an all-green field on both races for a profit of about $10.

I know this can be dangerous, but it might be something to keep in mind.