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.

Berkshire Hathaway disclosed several stock purchases (and one sale) during the first quarter. While investors will have to wait until May 15 for the full portfolio, they will be able to see if Buffett added to this other investment in the first quarter.