Investors often use Berkshire Hathaway's quarterly-filed Form 13Fs to track Warren Buffett's trading activity. Buffett has been a net seller of stocks for nine consecutive quarters, which has ballooned Berkshire's cash pile to $334 billion.

Tens of thousands of people will descend on Omaha, Nebraska, to attend the annual shareholder weekend for billionaire Warren Buffett's Berkshire Hathaway. Buffett, 94, is expected to answer shareholder questions over four and a half hours at Berkshire's annual meeting on Saturday.

Warren Buffett’s Berkshire Hathaway is set to hold its annual shareholder meeting and release its first-quarter financial results on Saturday. Investors will be watching closely to see what the "Oracle of Omaha" has to say amid economic uncertainty.