It's not clear to me whether you meant to accuse Mr. Buffet of criminal behavior, here. There is certainly public information that is harder to get than other public information, but trading on inside information is a crime.
Public / Private information is only an issue when companies are publicly traded.
If you go to buy a private company you can get a lot of non public information. The same thing happens when you try and take a public company private with the caveat that you can only use that information to back out of a deal not make your first offer. AKA, you get to do an audit after the terms where agreed upon and only get to back out of you discover major issues.
I suspect jayvanguard is not talking about Berkshire Hathaway's public company investments (for which I'm sure Buffett does not use material non-public information) but Berkshire Hathaway's private company investments and acquisitions. These make up more than half the company's market cap, I believe.
