First, the balance-sheet expansion of some $3.6 trillion since late 2008 – which far exceeded the $2.5 trillion in nominal GDP growth over the QE period – boosted asset markets. It was assumed that the improvement in investors’ portfolio performance – reflected in a more than threefold rise in the S&P 500 from its crisis-induced low in March 2009 – would spur a burst of spending by increasingly wealthy consumers.