volatility). Given the complexity of the calculations involved and the convoluted structure that a convertible bond can have, an arbitrageur often relies on sophisticated quantitative models in order to identify bonds that are trading cheap versus their theoretical value. Convertible arbitrage consists of buying a convertible bond and hedging two of the three factors in order to gain exposure to the third factor at a very attractive price. For instance an arbitrageur would first buy a convertible bond, then sell fixed income securities or interest rate futures (to hedge the interest rate exposure) and buy some credit protection (to hedge the risk of credit deterioration). Eventually what he or she would be left with is something similar to a call option on the underlying stock, acquired at a very low price. He or she could then make money either selling some of the more expensive options that are openly traded in the market or delta hedging his or her exposure to the underlying shares. Depository receipts A depositary receipt is a security that is offered as a "tracking stock" on another foreign market. For instance, a Chinese company wishing to raise more money may issue a depository receipt on the New York Stock Exchange, as the amount of capital on the local exchanges is limited. These securities, known as ADRs (American depositary receipt) or GDRs (global depository receipt) depending on where they are issued, are typically considered "foreign" and therefore trade at a lower value when first released. Many ADR's are exchangeable into the original security (known as fungibility) and actually have the same value. In this case, there is a spread between the perceived value and real value, which can be extracted. Other ADR's that are not exchangeable often have much larger spreads. Since the ADR is trading at a value lower than what it is worth, one can purchase the ADR and expect to make money as its value converges on the original. However, there is a chance that the original stock will fall in value too, so by shorting it one can hedge that risk. Cross-border arbitrage Cross-border arbitrage exploits different prices of the same stock in different countries: Example: Apple is trading on NASDAQ at US$108.84. The stock is also traded on the German electronic exchange, XETRA. If 1 euro costs US$1.11, a cross-border trader could enter a buy order on the XETRA at €98.03 per