“Stocks Might Be 50% Lower Without Fed”
They posted the following chart:
Clearly, the S&P 500 would have gone to zero (as indicated in the chart) if the fed had not pumped as much liquidity in the system as they have.
The reality is that fed money pumping probably had some positive impact on equities, but how much remains a question that will be impossible to verifiably answer. My guess is that it goosed up the US treasury bond market more so than equities.