Warren Buffett's firm to update its U.S. stock portfolio

OMAHA, Neb. Warren Buffett's company is expected to file a quarterly update on its U.S. stock portfolio on Wednesday afternoon.

Berkshire Hathaway's (BRK.A) investments are always watched closely because many people try to copy Buffett's moves.

The filing expected Wednesday will show the U.S. stocks Berkshire held at the end of March.

But the quarterly stock report won't distinguish between Buffett's stock picks and those made by the company's two other investment managers.

Buffett has said investments smaller than $300 million aren't likely to be his picks because he generally makes bigger investments. Berkshire has about $49 billion cash on hand giving Buffett plenty to work with.

Besides investments, Berkshire owns more than 80 companies; including insurance, utility, railroad, furniture, jewelry, manufacturing, restaurant and apparel companies.