As many people know, HFT( high frequency trading) use things, in order to get ahead of all other participants in the struggle for the execution of their orders by placing their orders for values less(more), than the increment( tick size). For example, if ask price 25, they use their programs to place orders for 24.9999 and thus get ahead of the crowd. To level the playing field for all participants( although HFTs will outperform due to the speed of the algorithms)exchanges start a company to allow decreasing the increment, so that everyone has the opportunity to place their orders for values less, how 1 cent.
www.cnbc.com/id/35072901
