Buffett reveals new investments

Warren Buffett is seen as one of the world's greatest investors

US billionaire Warren Buffett's investment firm has revealed new stakes in Nestle and Exxon Mobil.

Berkshire Hathaway said it held 3.4 million American depositary receipts - which represents shares in foreign companies - of Nestle, worth $144.7m.

It also reported owning 1.28 million shares in the oil giant Exxon Mobil, valued at $87.6m.

Stock picks by Mr Buffett are watched closely as he is considered to be one of the world's greatest investors.

The disclosures were made in a US Securities and Exchange Commission (SEC) filing.

Berkshire Hathaway also revealed that it had nearly doubled its stake in Wal-Mart, the world's largest retailer.

While Nestle, Exxon and Wal-Mart are all household names, their shares have lagged the broader US stock market in recent months.

Mr Buffett is known for buying even when economic conditions are weak, and one of his sayings is: "It is far better to buy a wonderful company at a fair price than a fair company at a wonderful price."

The SEC filing also showed that Berkshire Hathaway had reduced its stakes in oil company ConocoPhillips and credit ratings agency Moody's.