Apple's latest innovation ... a big stake for Berkshire

Buffett says he thinks it's too hard to determine what tech companies will be worth in the future because their businesses evolve so quickly, but he's certain Snickers candy bars and Coca-Cola will remain popular decades from now.

[...] the filing didn't disclose who made the Apple investment.

Besides Buffett, Berkshire has two other investment managers, who each handle about $9 billion.

IBM focuses more on software and technology services these days.

Besides investments, Berkshire owns more than 90 companies in a variety of industries, including insurance, utilities, BNSF railroad, furniture and jewelry.