An information diffusion model for momentum effect based on investor wealth

We propose a private information diffusion model to explain the momentum, which considers different amounts of investor wealth and uses the proportion of informed investors’ wealth to measure information diffusion speed. Different distributions of investor wealth can lead to different information diffusion processes, and the speed of information diffusion is positively correlated with the concentration of investor wealth. Our empirical results reveal the relationship between momentum return and information diffusion speed by the S&P 500 stocks in two periods of the upmarket. The results show that stocks with faster information diffusion speed gain higher time-series momentum returns, especially under short holding period strategies. These results provide new evidence for the correlation between information diffusion and the momentum effect.