I develop a two-period model of supply chain fragility. In the model, an exogenous shock can break a random link in the chain, in which case the flow goes through a new firm drawn out of a competitive pool. I show that (1) the more upstream the broken link is, the greater the loss on the final...

R&D consortia, which coordinate R&D activities of their member firms, have been successful in many industries. We study a model with two competing supply chains each consisting of a manufacturer and a supplier. The manufacturers compete in the final product market, and can conduct R&D to reduce...