Warren Buffett has long complained that Berkshire Hathaway has become so huge that it’s difficult to find acquisitions that are both undervalued and large enough to make a material difference to the company’s bottom line.

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.

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.