Demand shocks can originate from changes in things such as tax rates, money supply, and government spending.
[1] In the midst of a poor economic situation in the United Kingdom in November 2002, the Bank of England's deputy governor, Mervyn King, warned that the domestic economy was sufficiently imbalanced that it ran the risk of causing a "large negative demand shock" in the near future.
At the London School of Economics, he elaborated by saying, "Beneath the surface of overall stability in the UK economy lies a remarkable imbalance between a buoyant consumer and housing sector, on the one hand, and weak external demand on the other.
"[2] During the 2007–2008 financial crisis and the Great Recession, a negative demand shock in the United States economy was caused by several factors that included falling house prices, the subprime mortgage crisis, and lost household wealth, which led to a drop in consumer spending.
To counter this negative demand shock, the Federal Reserve System lowered interest rates.