THANKS TO the Internet, fans of Warren Buffett, the world's greatest stock market investor, no longer have to wait for the arrival of a bulky envelope every March to find out what he has to say in his Annual Report.

The report was published online on Sunday, and no doubt a good many of the 250,000 investors who now own shares in his company Berkshire Hathaway logged on to the site (http://www.berkshirehathaway.com) for their annual exposure to the great man's musings.

Buffett's annual reports are quite unlike those of any other public quoted company. There are no photographs of any description; nor are there any fancy graphs or charts. The document has clearly never seen the inside of a graphic design studio.

Such an idea would be anathema to a man who trades on his reputation for folksy Mid-Western thrift and rightly takes pride in the fact that his overheads are by far the lowest of any Fortune 500 company. (Despite sales of $14bn, Buffett solemnly records this year that the head count at his head office in Omaha, Nebraska has risen from 12 to 12.8 people, following the hiring of a four-days-a-week accountant).

While Buffett writes at length about his thoughts on current issues (this year the tour de force is a scathing attack on the way that managers manipulate their earnings figures), another distinctive feature of the annual reports is that he actually says very little about what he is currently up to as an investor.

This is for two reasons. One is that, as a long-term investor, with a portfolio of a few very large equity holdings that he likes to hold for many years, there is often little in the way of significant investment activity to report.

The second reason is that Buffett knows there is little to be gained - and plenty to be lost - by tipping the market's hand about what he might or might not be about to do. Such is his reputation that even the merest sniff of his involvement in a market can have a seriously distorting effect.

In any case, it is a long-established part of the Buffett style to downplay his track record and ambitions. This year, for example, he notes that the value of his equity holdings rose by less than the S&P 500, the bench mark index for the American market. His decision to unload shares in McDonald's actually cost shareholders money, he observes: they would have done better if he had "snuck off to the cinema instead".

He rounds this off with a now ritual warning that future performance will not match his 34-year track record of growing Berkshire Hathaway's book value per share by 24 per cent compound a year. The best he can hope to do in future, he says, is 15 per cent a year and even then there will be down years as well as good ones.

Don't be taken in by these protestations. The interesting thing for anyone who has followed Buffett's activities over the years is to see how he has been adapting his business to cope with the late cycle of the maturing bull market on Wall Street. As always it pays to look carefully at the numbers.

They show that while Buffett has in the main kept or even increased his holdings in his core long-term holdings (Coca-Cola, Gillette, American Express), for the past three years he has actually been a net seller of shares.

More importantly, he has been using his own highly valued shares to buy other companies. His big strategic move last year was the $22bn acquisition of a large insurance company, General Reinsurance, which fits neatly with his existing insurance interests.

His first step on taking control however was to sell the company's entire portfolio of shares (some $3bn-worth) and push the proceeds and the remainder of the company's huge cash flow into cash and bonds. At the year end, he had no less than $15bn sitting in cash or liquid investments; and $21bn in bonds across the whole range of maturities. This compares with the $37bn or so in assets that he has invested in the stock market and a roughly similar amount he now has tied up in the privately owned businesses he has been buying steadily over the years.

Whereas quoted shares used to count for 70-80 per cent of Buffett's investment business, now they account for little more than a third of Berkshire Hathaway's total assets.

Buffett says that he is now on the lookout for further big acquisitions or large investment opportunities. Like everyone else, I have no idea where his eye will alight next. But for my money, the way he has handled his portfolio over the past three years - using his shares to buy cash- rich insurance companies, reducing his equity exposure, parking money in bonds and loading up with private (ie non-traded) equity - is a text book study in how a consummate investor manages risk management in the later stages of a bull market.

Last time the stock market reached the giddy heights it is at now, which was the late 1960s, Buffett made a famous decision to return all his investors' money because he could no longer find anything to buy at a sensible price. It won't play out that way this time because the vehicle he uses now is a very different animal. But the days when one could think of Buffett as the archetypal stock market investor are clearly over. In my view, investors everywhere should take note and moderate their own approach to the stock market accordingly.