Berkshire Hathaway's (NYSE:BRK.A) (NYSE:BRK.B) latest Securities and Exchange Commission filing demonstrates that Chairman and uber-investor Warren Buffett is still unable to find suitably attractive investments in the equities market.

After selling off $430 million of equities in the fourth quarter of 2003, Buffett sold about $150 million of U.S. stocks between Dec. 31, 2003, and March 31. While the $150 million sold represents only a small fraction of Berkshire's $35 billion portfolio, it is important to keep in mind that most of that portfolio comprises what Buffett has termed "permanent" holdings for Berkshire. These are shares in companies such as Coca-Cola (NYSE:KO) and The Washington Post Co. (NYSE:WPO), many of which he has held for decades.

Berkshire sold off all of its shares in two companies: Automatic Data Processing (NYSE:ADP) and Dover (NYSE:DOV). Buffett had begun reducing his position in both companies in the previous quarter. These two stocks have outperformed the Standard & Poor's 500 in the last year, and both are richly priced today. ADP currently trades at 3.5 times sales with a trailing P/E of 29, while Dover stock trades at 1.6 times sales with a trailing P/E of 25.

Berkshire also continued to make reductions in its holdings in two other stocks, H&R Block (NYSE:HRB) and Zenith National Insurance (NYSE:ZNT), after selling off shares of both companies in the fourth quarter. However, Berkshire still holds a significant position in H&R Block, valued on March 31 at over $730 million. The company's position in Zenith is down to under $5 million, and my expectation is that Berkshire will fully exit that stock shortly.

In addition, although Berkshire's cash position increased to a staggering $41 billion in the latest quarter, the company did not make any additions to its equity portfolio.

As I have written in previous articles, investors who are actively buying any of the stocks that Berkshire is selling are essentially betting against Buffett -- a rather bold gamble. And all investors should be conscious of the fact that even with $41 billion burning a hole in his pocket, Buffett is struggling to find opportunities to invest in the U.S. equities market.

Do you agree with Buffett's moves? Join the conversation on the always-interesting Berkshire Hathaway discussion board.

Fool contributor Salim Haji lives in Denver, Colo. He owns shares in Berkshire Hathaway. His current cash position is, sadly, somewhat less than $41 billion.