NEW YORK (CNN/Money) - When Warren Buffett's letter to shareholders comes out each year, investors around the world sit up and take notice.

After all, the "Oracle of Omaha" has been writing letters to Berkshire Hathaway shareholders for 38 years. and over that time he's become the world's second-richest man and one of its most widely followed investors.

Click on the picture for more on Buffett's letter

In this year's letter, officially released Saturday (with an exclusive sneak peak offered last week at Fortune.com), Buffett covered a wide range of topics.

Perhaps of most interest was that in 2002, Warren Buffett made few changes to Berkshire Hathaway's largest stock positions.

The major positions, those in which Berkshire has a stake greater than $500 million, are American Express, Coca-Cola, Gillette, H&R Block, Moody's, Washington Post and Wells Fargo. Making it into the list of top holdings in 2002 was M&T Bank, a bank holding company based in Buffalo, N.Y.

Berkshire's largest holdings Buffett isn't selling -- but thinks overall valuations still haven't come down enough. Company (ticker)  Shares  Value  American Express (AXP)  151,610,700  $5.4 billion  Coca-Cola (KO)  200,000,000  $8.8 billion  Gillette (G)  96,000,000  $2.9 billion  H&R Block (HRB)  15,999,200  $643 million  M&T Bank (MTB)  6,708,760  $532 million  Moody's Corp. (MCO)  24,000,000  $991 million  Washington Post (WPO)  1,727,765  $1.3 billion  Wells Fargo (WFC)  53,265,080  $2.5 billion   values as of 12/31/2002  Source:  Berkshire Hathaway

Though Buffett did not sell, he noted that valuations still had not come down enough to justify adding to stock current positions -- or to stocks in general.

"Despite three years of falling prices, which have significantly improved the attractiveness of common stocks, we still find very few that even mildly interest us," the report reads. "That dismal fact is testimony to the insanity of valuations reached during The Great Bubble. Unfortunately, the hangover may prove to be proportional to the binge."

Buffett also has choice words on corporate governance, that is, the role corporate boards play in supervising the actions of managers. Citing his 1993 shareholder letter, Buffett writes, "If able but greedy managers over-reach and try to dip too deeply into the shareholders' pockets, directors must slap their hands." Since first writing that, Buffett says, "over-reaching has become common but few hands have been slapped."

Buffett blames the "boardroom atmosphere" in which collegiality wins out over shareholder interests, and focuses most on compensation committees.

"In recent years, compensation committees too often have been tail-wagging puppy dogs meekly following recommendations by consultants, a breed not known for allegiance to the faceless shareholders who pay their fees.... Directors should stop such piracy...It would be a travesty if the bloated pay of recent years became a baseline for future compensation."

Buffett offers three suggestions for investors. First, beware of weak accounting. Watch out for companies that don't expense stock options and those that make aggressive projections on pension funds. Those are just two measures, but as Buffett writes, "when managements take the low road in aspects that are visible, it is likely they are following a similar path behind the scenes. There is seldom just one cockroach in the kitchen." Buffett also cautions against companies that trumpet EBITDA.

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The second suggestion is to avoid companies with unintelligible footnotes to their financial documents. "Enron's descriptions of certain transactions still baffle me," Buffett writes.

Finally, watch out for companies with managements that make much of earnings projections and growth expectations. "Managers that always promise to 'make the numbers' will at some point be tempted to make up the numbers."

For more on Buffett's letter, click on these links to Fortune.com:

• Avoiding a 'mega-catastrophe' - Buffett says derivatives like rate swaps and futures and options -- tools used by many professional investors -- are latent dangers that could become lethal.
• Buffett on stocks today - "Unfortunately, the hangover from [the market bubble] may prove to be proportional to the binge."
• Berkshire Hathaway and junk - Buffett's holding company has been making what he calls "sensible investments" in a few junk bonds and loans.