Number of horses in a race and pre race market volatility

[kenfrost]

Is there an inverse correlation between the number of horses in a race and the pre race market volatility (ie the more horses the less volatile)?

Or am I just imagining this?

[Dallas]

Yes, smaller fields are more volatile than larger ones as any movement on one runner has a greater impact on the others if there are only 3-4 others in the market compared to there being 12+ and several of them can absorb the move

[kenfrost]

Yes, smaller fields are more volatile than larger ones as any movement on one runner has a greater impact on the others if there are only 3-4 others in the market compared to there being 12+ and several of them can absorb the move

Thanks, that's what I intuitively was thinking but it is good to have it confirmed

[Anbell]

More specifically, the shorter the price of the favourite, the more volatile the market. In smaller fields, the favourite is usually shorter, and therefore the market is usually more volatile.

[kenfrost]

More specifically, the shorter the price of the favourite, the more volatile the market. In smaller fields, the favourite is usually shorter, and therefore the market is usually more volatile.

Thanks

[Anbell]

More specifically, the shorter the price of the favourite, the more volatile the market. In smaller fields, the favourite is usually shorter, and therefore the market is usually more volatile.

(and also, as Dallas says, the smaller fields mean greater whiplash because any change in the favorites have to be absorbed by fewer alternatives)