> good example in the book explaining why a tick size is needed. > Say that the current bid in the market is $20. If you want to buy at that price, you will be placed last in the list of orders. But since the sorting order is first by price, then by arrival time, you could get first in line by putting in an order with a price only slightly better than $20 (say $20.00000001).

I don't buy the argument.

Removing tick (or at least reducing it 100x) would put more emphasis on price discovery instead of speed.