This article presents results of tests on two related hypotheses on money supply. The first relates to an unresolved issue of money endogeneity while the second centres on the yet-explored relationship between money supply and bank stock returns if money is found to be endogenous. Our results, using long-horizon data of Group of Seven (G-7) economies, supports causality in money supply as running from bank lending to bank deposits, a result that is predicted by the post-Keynesian money supply endogeneity (bank-credit-driven) theory. Thus, the result is not consistent with exogeneity proposition. A new evidence of positive relationship between endogenous money supply and aggregate bank stock return is statistically significant on this hitherto unexplored topic. These findings are consistent with the post-Keynesian money supply theory and the dividend valuation theory, which predicts money supply changes to induce changes in bank earnings, so bank share prices change.