Several exchanges offer a make-take price differential. Intersango,
bitfloor and hellobitcoin come to mind.
I feel that the differential they choose is somewhat
I have always felt that the make-take commission differential should
be no greater than the exchange's least count divided by the price of
btcusd. And, all exchanges violate this condition.
Why do I belive in this condition? For if this condition is not
met, then as a trader, it sometimes is cheaper for you to bid at
6.51 than it is to bid at 6.50.
Equivalently, here's, I believe, the problem from the exchange's
perspective if you violate this condition. The make-take difference may help you achieve a tight
spread and thus, a good price-discovery, but both are illusory
imagine that the true bid-ask frontiers should lie at
6.51-6.52. Imagine that your exchange is currently locked in at
6.50-6.51. Your exchange has seemingly discovered a price with a tight
spread. Is this the correct price? Even if traders are convinced that
the correct frontier should be 6.51-6.52, there is a *negative*
incentive for a trader to try to correct that imbalance.