A Debt Crisis with Strategic Investors: Changes in Demand and the Role of Market Power

This paper documents changes in investors' demand for sovereign debt during a debt crisis. Using a dataset containing individual bids on Portuguese debt auctions, I document that bid functions become more inelastic during the crisis. That is, investors require bigger drops in price to buy additional units of debt, increasing the government’s marginal cost of issuing debt. I then decompose these changes in demand into two components: a fundamental component, due to changes in the valuation of the security, and a strategic component, that arises from investors' market power. I find that, although the role of market power is negligible in normal times, it gets more pronounced leading up to and during the crisis. The government is not able to extract the full surplus from strategic investors, and, as a result, the auction mechanism loses efficiency during that period. Finally, I discuss a possible mitigation strategy. Everything else constant, the use of shorter maturities could avoid higher inefficiency costs.