What is interesting is whether the Fed’s massive balance sheet actually stimulates economic activity. Its massive QE asset purchases following the GFC (QEII and QEIII) did not generate any acceleration in nominal GDP, so inflation remained below the Fed’s 2% target. In a sense, the Fed’s great balance sheet expansion “worked because it didn’t work”. If its post-crisis QEs had actually stimulated the economy as the Fed’s models had predicted, the economy would have boomed and inflation would have risen materially, and the Fed would have been forced to raise rates and unwind its balance sheet. That did not happen, so the Fed is willing to play the same angle today. (The Fed has become adapt at Washington politics: if there is not a sustained acceleration in nominal GDP, the Fed will say that if it had not maintained such a large balance sheet, economic and labor market conditions would have been much worse; if the economy accelerates and inflation rises, the Fed will take credit for the improvement.)