A dynamic model with credit under limited commitment is constructed, in which limited memory can weaken the effects of punishment for default. This creates an endogenous role for government debt in credit markets, and the economy can be non-Ricardian. Default can occur in equilibrium, and government debt essentially plays a role as collateral and thus improves borrowers' incentives. The provision of government debt acts to discourage default, whether default occurs in equilibrium or not.

We develop a parsimonious model to study the effect of regulations aimed at reducing counterparty risk on the structure of over-the-counter securities markets. We find that such regulations promote entry of dealers, thus fostering competition and lowering spreads. Greater competition, however, has an indirect negative effect on market-making profitability. General equilibrium effects imply that more competition can distort incentives of all dealers to invest in efficient technologies ex ante and so can cause a social welfare loss. Our results are consistent with empirical findings on the effects of post-crisis regulations and with the opposition of some market participants to those regulations.