(Reuters) - Conglomerate Berkshire Hathaway
"Our preference at Berkshire is to keep buying big operating businesses," the billionaire investor said in an interview on CNBC. "In terms of building Berkshire for the long term, we just like adding earning power, big chunks of earning power."
However, he added that stock holdings were "generally for very long term."
The interview came two days after Buffett released his annual letter to shareholders, in which he signaled that his hunt for "elephants," or large acquisitions, continues.
That business-buying strategy has helped Buffett build Berkshire over the decades so it now holds dozens of businesses, from ice cream to insurance.
With Berkshire's range of businesses and stock holdings, some analysts compare Berkshire to an index fund tied to the health of the U.S. economy, the world's biggest, in which Buffett has expressed strong optimism in recent years.
But as Berkshire has grown, regulators are now weighing whether Berkshire Hathaway should be considered a systemically important financial institution, or one that is too big to fail, Bloomberg reported earlier this year.
"We've heard absolutely nothing from the people in charge of what's called SIFI," Buffett said on CNBC on Monday.
As he's done over the years, Buffett encouraged investors of all sizes and stripes to put their money to work, potentially earning greater returns than by simply holding cash.
Still, in emphasizing productive assets, he noted at least one investment in which he is not bullish: bitcoin.
"It's not a currency," he said flatly.
Mt. Gox, once the world's biggest bitcoin exchange, filed for bankruptcy on Friday, underscoring the growing pains facing the world of cryptocurrencies.
"I wouldn't be surprised if it's not around in 10 to 20 years," he added.
(Reporting by Luciana Lopez and Sam Forgione; Editing by Chizu Nomiyama and Nick Zieminski)