Less Is More: Forecast Granularity, Estimation Error, and Portfolio Choice
Each dimension of a return forecast an investor acts on costs 1/T, whatever signal it carries. Setting the number of rank groups from the forecast’s information coefficient, and holding 1/N when the forecast cannot rank, earns an annualized Sharpe ratio of 1.2 on a hundred large CRSP stocks, against 0.6 for 1/N and 1.0 for the decile sort.












