Berkshire Hathaway (BRK-A) also reduced its stake in snack-foods maker Mondelez International Inc. (MDLZ) and made several other adjustments to its $85 billion U.S. stock portfolio during the first quarter. The changes were disclosed Wednesday.
At the end of March, Berkshire held 6.5 million shares of engineering and construction firm Chicago Bridge & Iron and 5.6 million shares of movie network Starz.
Berkshire cut its Mondelez stake to 7 million shares from 12.8 million at the end of 2012.
Berkshire's investments are closely watched because many people try to copy Buffett's moves. But because many of the firm's latest investments are smaller than $500 million, they are likely the work of Berkshire's two other investment managers.