The road to extinction: commons with capital markets

Competitive agents extract in continuous time from a commons. Capital market access allows them to both save and borrow against their extraction stream. When the commons asset grows more quickly than the privately stored one, multiple equilibria are found for intermediate commons endowments. One of these has the extinction date and welfare decrease in the endowment, a resource curse. When the commons asset grows less quickly than the privately stored one, there is a unique extinction date for each endowment level. In the limit, as marginal extraction costs become constant, `jump extinctions' occur. In cases with multiple equilibria: welfare is increased for low initial stock levels when agents do not have access to capital markets, but decreased otherwise; and an extraction tax reduces welfare in the `cursed' equilibrium, increases it in the other finite extinction equilibrium and expands the set of commons stocks that are never extinguished