Warren Buffett usually steers clear of buying companies from private equity firms, which, he said famously in 2010, are too focused on exits. But the billionaire businessman made an exception when his Berkshire Hathaway Inc. (NYSE: BRK.A, BRK.B) agreed in November to acquire Oriental Trading Co., the largest shareholder of which is Kohlberg Kravis Roberts & Co. (NYSE: KKR).

Based in Berkshire and Buffett's home town of Omaha, Oriental Trading sells party supplies, arts and crafts, school supplies, toys and novelties, including themed gift bags, dinosaur pinatas and glow-in-the-dark jewelry. The company offers guaranteed lowest prices on its more than 40,000 products.

"By increasing revenue, profits and the customer base over the last few years, Sam Taylor and the entire Oriental Trading team have successfully improved the business and positioned it for long-term growth," Buffett says.

Oriental Trading emerged from bankruptcy protection in 2011, after filing for Chapter 11 protection in August 2010. KKR owned about a one-third stake, after the firm exchanged its debt for equity when the company exited from bankruptcy.

Berkshire Hathaway's businesses include property and casualty insurance and reinsurance, utilities and energy, freight rail transportation, finance, manufacturing, retail and other services.