This thesis investigates the effect of credit default swaps on firm behaviour. A credit default swap (CDS) is an insurance contract under which buyers make periodic payments over the contract's life to insure against credit events related to the underlying entities. As an efficient tool for lenders or bond investors to hedge the credit exposures associated with their investments in a firm while maintaining their control rights, the market for CDSs has developed quickly over the last two decades. The impact of this new but fast-growing credit derivative market has attracted considerable attention from financial researchers. This thesis contains five chapters. Chapter 1 presents a brief introduction to CDSs and the research questions. Chapter...