We develop a dynamic equilibrium model of complex asset markets with endogenous entry and exit in which the investment technology of investors with more expertise is subject to less asset-specific risk. The joint equilibrium distribution of financial expertise and wealth then determines this asset market’s risk bearing capacity. Higher expert demand lowers equilibrium required returns, reducing overall participation. In a dynamic industry equilibrium, investor participation in more complex asset markets with more asset-specific risk is lower, despite higher market-level Sharpe ratios, as long as asset complexity and expertise are complements. We analyze how asset complexity affects the stationary wealth distribution of complex asset investors. Because of selection, increased complexity reduces expertise heterogeneity and wealth concentration, even though the wealth distribution for more expert investors has fatter tails.