We model a public limit order book (PLB) with rational investors choosing to supply or demand liquidity. Following a reduction in the tick size the effects on PLB's market quality depend on the liquidity of the stocks. Spread improves for tick-constrained stocks and deteriorates for...

We develop a model where a public limit order book (PLB) competes with a Sub-Penny Venue, which allows Sub-Penny Trading (SPT). SPT occurs when a trader undercuts orders in the PLB by less than one penny, a practice we call queue-jumping (QJ). QJ is higher for NASDAQ than for NYSE stocks. We...