Chart courtesy of Fidelity InvestmentsThe S&P 500 prints a new high while G4 central bank liquidity provisions, to support economic growth, remain weak. The Fed and the ECB have signaled a dovish tilt, but are seemingly behind the curve in providing necessary liquidity to foster economic growth as they have in years past. Since 2011, G4 central banks have expanded their balance sheets to support economic growth and risk assets. The right-side of the chart shows largely the results of the Fed's balance sheet normalization; liquidity as tightened. Will global economic growth continue without the G4 banks buying more assets? I think not. Economic growth since the GFC has been a function of central bank asset purchases; as such, at the very least, the U.S.benchmark interest rate returns to the lower bound.