"Capital Structure Arbitrage" is an example of an arbitrage strategy that uses CDS transactions. This technique relies on the fact that a company's stock price and its CDS spread should exhibit negative correlation; i.e., if the outlook for a company improves then its share price should go up and its CDS spread should tighten, since it is less likely to default on its debt. However, if its outlook worsens then its CDS spread should widen and its stock price should fall.