Investors love the Cairo & Alexandria Stock Exchanges. The index of Egypt's 30 largest companies, the Case 30, has grown sevenfold since the country's liberalising executive government was appointed in July 2004.

However, the successes of the past four years should worry investors, rather than encourage them to take increasingly larger bets on the index.

Downturns are inevitable in all financial markets. Investors who make fortunes by selling at the peak of the market often do so out of luck rather than good judgment.

But this does not mean investors should stay away from the Case. Investment in Egypt has a long-term future because of the country's great advantage over its neighbours: its 80-million-strong population.

The bull market in equities will encourage more private companies to float. Hopefully, some of these businesses will come from outside the sectors that are already well represented on the stock exchange.

A greater range of sectors would do much to erase concerns about the Case 30's concentration on a handful of industries.

The greatest prize is the privatisation of state-owned enterprises, with Banque du Caire expected to be sold off in weeks.

The government would benefit from high prices if it sells now. The money could cut its budget deficit, equipping the economy for the bear market that will inevitably come.