In the 2007 Top Companies survey we noted that it had been four good years for the bulls, and that unprecedented confidence in the SA business environment was being translated into investment and expansion, led by government spending. In 2005, we remarked on how, when analysing investment prospects, the emphasis had shifted from extraneous factors like interest rates, inflation and commodity prices to the capacity of companies to do well in all conditions.

But good times don't last forever and we asked whether the bears were now lurking. It is a peculiar human characteristic - perhaps especially prevalent in business people - to develop a kind of amnesia when cycles turn. When times are good you forget that they were ever bad, and vice versa.

The first half of 2007 heralded a reversion to the gloomy mood of the early 2000s. Then there were concerns about low growth and what seemed to be a chronically weak rand. People spoke with authority of a "one-way bet downwards" for the currency, at a time when it was costing R14 to buy a US dollar and nearly R20 to get a pound sterling. Alongside this was a deep pessimism about the country's political prospects and a general lack of confidence.

This time around the depression has been prompted by several factors that happened to come into play at about the same time:

• Uncertainty over the succession to the ANC leadership;

• The astonishing disruption caused by the power failures of late January and early February, followed by the exposure of Eskom's severe weaknesses in management;

• The double whammy of soaring food and oil prices;

• The ability of Zimbabwe dictator Robert Mugabe to survive and continue ruining his country;

• "Xenophobic" riots and murders which also exposed the weakness of government in terms of policy processes and capacity to deal with social problems;

• Ominous remarks from the Reserve Bank governor about more interest rate increases; and

• Bad news about declining vehicle sales and property values, in addition to increases in bad debts.

Though it all seemed so sudden, not all of this was surprising. After all, the Jacob Zuma challenge to President Thabo Mbeki as leader of the ANC, and the resentment against immigrants, had been brewing for months, even years. Eskom had warned in 1998 of a looming power shortage. And, as we pointed out on this page a year ago, credit extension was getting tighter, inflation had already jumped above 6%, interest rates were seeing upward pressure, and food and oil prices were stubbornly high. Of course, nobody foresaw the degree to which all these problems would manifest themselves, but we cannot pretend that the warning signs were not there.

It is in this context that we present our annual snapshot of the performance, by various measures, of SA's leading companies. In the end, the real measure of an economy's health is not to be found in the seemingly endless procession of surveys, both quantitative and qualitative, that tell us interesting things about household indebtedness and business confidence and tax. The wise executive will take account of all the noise, of course, but his main concern will be his business - driving it, adapting it, hiring the right people and getting them to do the right things.

In all the years that Top Companies has been published, the top achievers have consistently performed in all conditions. Often they have low profiles. They focus in a disciplined way on what they do best and they aren't afraid to embrace change. They refuse to be content with merely being good, and they decline to make excuses when things go wrong.

In a sense, all ships were taken higher in the bull run between 2003 and 2007, and it was often not easy to see the real value. Now things are getting much more interesting. That is why here we offer a review of what happened, in the certain knowledge that this will not necessarily govern what is going to happen.

And it's always worth remembering the advice of the greatest individual investor of them all, Warren Buffett: Don't worry about the market, look at the individual companies and the people running them if you want value. He also said you shouldn't buy a share if you are not prepared to be holding it a decade from now.

Investors all have different needs, of course, but they all benefit from information and judgment. We trust we have provided both in abundance.