Buffett ups his stake in Wal-Mart

Billionaire Warren Buffett&rsquo;s vehicle Berkshire Hathaway has made new investments in Nestl&eacute; and Exxon Mobil, and&nbsp; nearly doubled its investment in Wal-Mart.<br /><br />In a US Securities and Exchange Commission (SEC) filing, Berkshire said it held 3.4m American depositary receipts of Nestl&eacute;, worth $144.7m (&pound;86.2m), at 30 September.<br /><br />It also reported owning 1.28m shares of Exxon Mobil, the world&rsquo;s largest oil company, valued at $87.6m.<br /><br />Berkshire also boosted its stake in Wal-Mart, the world&rsquo;s largest retailer, by 90 per cent from three months earlier, to 37.8m shares worth $1.86bn.<br /><br />ccccWhile the companies are all household names, their shares have lagged the US stock market since it bottomed in March. Buffett favours undervalued stocks, and regularly buys even when economic conditions are weak.<br /><br />But the world&rsquo;s second-richest person does not publicly discuss what he is buying and selling, or explain his purchases.a