We investigate competition between traditional stock exchanges and new ‘dark' trading venues using an important difference in regulatory treatment. SEC required minimum pricing increments constrain some stock spreads, causing large limit order queues. Dark pools allow some traders to by-pass...

We analyse the impact of two major financial frictions on market quality in a high-frequency environment: market fragmentation and exchange fees. We find fragmentation significantly improves market quality, with benefits increasing with greater fragmentation. Fragmentation significantly reduces...

We show that economically insignificant tick sizes encourage undercutting behavior, harming market quality. While theory shows increasing tick sizes in unconstrained markets reduces undercutting, improving market quality, pricing grids of most markets are too coarse to test this. We examine a...