Business leaders should be careful not to impose their personal views on their organizations, billionaire investor Warren Buffett told CNBC on Monday as companies sought to distance themselves from the National Rifle Association after the mass shooting at a high school in Flordia.

"I don't believe in imposing my views on 370,000 employees and a million shareholders. I'm not their nanny on that," the chairman and CEO of Berkshire Hathaway told "Squawk Box."

Still, Buffett, who supported Democrat Hillary Clinton during the 2016 election, said he doesn't think leaders should put all of their views aside at the door.

"People individually should very much express their views," he said. "I don't think that Berkshire should say we're not going to do business with people who own guns. I think that would be ridiculous."

Seventeen students and faculty members were gunned down on Feb. 14 when a gunman opened fire at Marjory Stoneman Douglas High School in Parkland, Florida.

Delta and United Airlines ended discounts for NRA members over the weekend. Big passive investors in the gun industry are also indicating they may take action. BlackRock's Larry Fink revealed plans to speak with gun makers the firm holds through its exchange-traded funds.

The move by BlackRock, the world's largest asset manager, is part of founder and CEO Larry Fink's bigger push for societal improvement. Fink sent a letter last month to the chief executives of the world's largest public companies, calling for them to help improve society or risk losing support from the firm.

"You have to be pretty careful if you're saying that you're not going to fly on this airline because of that or we're not going to use this railroad because of that," said Buffett. He added that he doesn't think Berkshire owns any gun investments.

Buffett was interviewed by CNBC in Omaha, Nebraska following the release of his highly anticipated annual letter to Berkshire shareholders.

He also spoke on these topics in the CNBC interview Monday:

— When choosing between stocks and bonds 'I would choose equities in a minute'

— I don't think Berkshire should avoid doing business with people who own guns

— The new GOP tax law benefits Berkshire and acts as a 'huge tailwind' for businesses

— There are three ways to go broke: 'liquor, ladies and leverage'