This paper provides estimates of monthly risk premia required by investors on shares, corporate bonds and government gilts during the period 1969–1987, based on the CAPM and using deviations between past actual returns and the model's forecast returns as inputs. Ex-ante risk premia increased dramatically during the 1970s and again on equities in the period around the October 1987 Crash. The risk premia moved closely in line with inflation in the 1970s, casting considerable doubt on the Modigliani and Cohn thesis that the fall in share prices in the middle of that decade was due to the market suffering from money illusion. When account is taken of trends in the premia and inflation timeseries, the correlation between the two disappears. This result is consistent with the findings of others that the widely observed negative correlation between share returns and inflation is a spurious one, traceable to monetary accommodation of supply-side shocks to the real economy — something which is hard to reconcile with the money illusion argument.