Market price determination: Interpreting quote order imbalance under zero-profit equilibrium

Abstract

We address the challenge of accurately determining market prices in order-driven markets, where the granularity of price adjustments is set by exchange rules, such as minimum increments of 0.01. Our approach advances traditional pricing models in accuracy by interpreting the dynamics of quote order imbalance, defined as the difference in volume between buy and sell orders at the best available prices, within a zero-profit equilibrium framework. This framework assumes that market competition leads to a state where no additional profit can be made from these imbalances. Analyzing high-frequency data from China's A-share market, we demonstrate the variable impact of order imbalances on price formation, influenced by the depth and liquidity of the market. We also uncover a potential threshold effect of order flow autocorrelation on pricing. Our findings enhance market microstructure research and high-frequency trading strategies by offering a valuable tool for understanding price formation's complex dynamics.