Dolus and Guitar Jim. We all know the bookies make an over-round book and then let the odds fluctuate as demand waxes and wanes, hoping to end up with a situation where any result is a winner for them. However (please think about this Jim), as Dolus noted the bookies were getting a caning in the first seven races in his example. They were NOT succeeding despite the over-round. The reason is simple: they were making mistakes vis-a-vis the punters.
For example, Jim, they may have had a $3 fav (ie33%) and seven other runners in the first race at $7 (ie 7 x 14% =98% ) which means a "book" of 131%. What they want is only 25% of the money on the fav so that IF it wins their liability will be only 75% of the money bet and they'll have 25% profit. Of course they also want about 11% of the money on each of the others so that on each of them it's only 77% liability. Unfortunately a large amount of well-informed money (ie you or me) thought the fav was really an even money shot AND BET THE LOT. The bookies were now left with 50% of the money on the fav (ie 150% liability), furiously shortening the price, but all too late. Race after race it goes something like this. Comes the last race and the very same situation EXCEPT one of the $7 pops gets up (Horse H) and finally the bookies cheer!! UNTIL the bookies clerk leans across and says "we didn't get 11% for each of the seven non-favs, we only got 5% on B,C,D,E,F and G but someone plonked 47% on H =77% (now it's a massive and total annihilation). This is a result of we, the punters being as well informed as the bookies, framing our own(better) market and awaiting the right time to move (ie not necessarily betting BIG unless we are "sure" we have an edge).
Of course,this rarely happens but IT COULD. Why doesn't it? Any ideas? Or, even if the "mass" of punters are not smart enough to see the 2-1 fav as being dramatic overs (ie it should be evens) and then there is no 50% of the money landing on it, why can't you or I be perennially on the "right ones"?
Let me know further. Cheers.