The Johannesburg Stock Exchange is the largest exchange in Africa and among the top ten largest in the world. The exchange trades shares for a wide variety of industries, with the largest portion of market capitalization coming from the mining industry. The JSE just recently became a publicly held company in July or 2005.
The JSE lists shares on two separate markets, the Mainboard and AltX. The requirements for listing on the Mainboard are strict, while the AltX lists smaller companies who fail to meet the Mainboard criteria. As a new branch of the JSE, AltX companies currently make up a very small portion of JSE listings.
The exchange is fully electronic, using the JET System (Johannesburg Equities Trading). This is an order-based system, whereby trades are automatically executed when matching buy and sell prices are found.
Naked options trading is very risky - many people lose money trading them. It is recommended contacting your broker or investment professional to find out about trading risk and margin requirements before getting involved into trading uncovered options.