What is a 'Supply Shock'
A supply shock is an unexpected event that changes the supply of a product or a commodity, resulting in a sudden change in its price. Supply shocks can be negative (decreased supply) or positive (increased supply); however, they are almost always negative and rarely positive. Assuming aggregate demand is unchanged, a negative supply shock in a product or a commodity causes its price to spike upward, while a positive supply shock exerts downward pressure on its price.
BREAKING DOWN 'Supply Shock'When output is increased, the price of the good decreases due to a shift in the supply curve to the right, and the reverse is true when output is decreased. Supply shocks can be created by any unexpected event that constrains output or disrupts the supply chain, including natural disasters and geopolitical developments such as acts of war or terrorism. A commodity that is widely perceived as being the most vulnerable to negative supply shocks is crude oil, since most of the world's supply comes from the volatile Middle East region.
Examples of Supply Shocks
The global salmon industry is currently experiencing a supply shock. A deadly algal bloom has killed over 27 million salmon in Chilean salmon farms as of March 10, 2016. These salmon losses amount to a supply contraction of 6.8% in 2016.
The struggles of a single firm can cause a supply shock too if the company is big enough, as has been the case in the copper industry since Glencore announced in September 2015 of its plans to close two major copper mines in the Democratic Republic of Congo and Zambia, removing 400,000 tonnes of copper from global output. This decision comes as a response to a prolonged slump in copper prices, so this particular supply shock is looked upon by competing firms as beneficial.
The fall in copper prices was caused by a slowdown in Chinese demand for copper, which for the past decade grew at an annual rate of over 10% until it dropped to 3 to 4% in 2015, which highlights how a concentrated change in demand can influence prices as well. A change in demand has to be abrupt and perceived as temporary to qualify as a shock, as is the case on the supply side.
Events such as the flight of refugees from Syria caused a shock to labor supply in Syria, driving up prices, and a demand shock in the countries they are fleeing to, driving up prices of goods and services.