Four years ago, we reflected in this space on the "irrational negativity" of the financial markets. "These days," we said ruefully in June 2003, "most JSE-listed companies have to pay you to invest in them." From the perspective of 2007, that seems a long time ago, in a galaxy far, far away.

There were many things to grumble about then. Nobody expected the bulls to run as they did for the next few years. In retrospect, as always, there were some fantastic buying opportunities. As business legend Harry Oppenheimer liked to remark, the only difficult thing in business and investment is the timing.

This annual survey of SA's leading companies is essentially about what they have done, not what they want to do. The record is not easy to capture. The fortunes of any company are constantly changing. It is always going to be artificial to try to freeze the business environment at a particular point. But when all the information is taken together, we have a snapshot of the listed corporate scene that gives a unique perspective.

As this year's Top Companies cover indicates, it has been a good four years, and the pessimism and inertia of 2003 seems far away.

Money was being made, even then. For instance, gold had already reasserted itself as an investment asset. But the mining sector, then as now, saw itself as vulnerable to rand strength and scary legislation. The stirrings of a great commodity boom were hardly noticed. We wrote gloomily in 2003 that SA "cannot rely on buoyant world demand for its exports and will probably have to turn inwards if it wants to sustain the economic growth rates it has achieved in the past few years." In fact it was able to do both.

In the 2004 Top Companies, we reflected worries that interest rates would rise (in fact they were on a downward path); that the commodity boom would end because of overheating in the Chinese economy (it got hotter without killing demand); and that inflation would go up (it did not).

Government's promised infrastructure spending still seemed like a mirage in the desert. Oil was trading at US$40/barrel - and we thought that was high (by mid-2006 it had nearly doubled, and at the start of June this year it was at $70).

But in 2004 consumer confidence was surging; national treasury admitted that its estimate of 2,9% growth had been too low; and we saw the start of a period where companies' earnings consistently exceeded their own forecasts. Scepticism turned to confidence, then to exuberance.

By 2005 it was clear that a strong bull run had begun in 2003 and that the finish line was not yet in sight. Business confidence was probably at its strongest since the 1970s, certainly since the transition to democracy in the 1990s. There was unqualified admiration for the way fiscal and monetary policy had been handled by government. The record of the SA Revenue Service in consistently exceeding collection targets was a source of pride and awe (and fear in some quarters). Interest rates and inflation were at their lowest in decades and the levels looked sustainable. The property sector, recovering from decades of hesitancy, continued to roar ahead.

In the 2005 Top Companies 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. Big corporate ambassadors like SABMiller, Anglo American and Old Mutual were among those putting into global practice their conviction that a really good company is able to thrive in all conditions.

By 2006 it was clear that the unprecedented confidence in the SA business environment was being translated into investment and expansion, led by government spending. Even the deep and at times desperate concern over crime and a dismal education system failed to dent the surge. Problems that had hardly been imagined in 2003 - such as an acute skills shortage - were being faced with a "can-do" attitude.

So it has been four years for the bulls. As if to celebrate, the Bulls rugby team brought the Super 14 trophy to SA for the first time.

Are the bears lurking? It's true that credit extension is getting tighter, inflation has jumped above 6%, interest rates are seeing upward pressure, food and oil prices are stubbornly high. But many of the positive factors identified above remain. Whatever your call on the timing of the downturn, you will need to be more careful in selecting stocks that will do well in all conditions - and there can be no better guide than this edition of Top Companies.