“Supply networks are inefficiently, and insufficiently, resilient,” says a group of researchers including Nobel Prize winner Joseph Stiglitz, in a paper published by the US Federal Reserve.

The paper’s other authors are Agostino Capponi, a professor at Columbia University, and Chuan Du, an economist with the Fed.

The authors say when “upstream” firms, that work with rawer materials, underinvest in production capacity, they can defend their profit margin by charging higher prices. Conversely, when