Warren Buffett.REUTERS/Rick Wilking Warren Buffett's Berkshire Hathaway added a trio of homebuilders to its portfolio last quarter. The investor's company exited three stocks and slashed several other positions, SEC filings show. Berkshire also boosted its Capital One and Occidental Petroleum stakes last quarter. Warren Buffett's Berkshire Hathaway pruned its stock portfolio last quarter, swapping out three positions and slashing several existing ones.