Watch CNBC's full interview with legendary investor Mario Gabelli

Mario Gabelli, chairman and CEO of Gamco Investors, joins CNBC's 'Squawk Box' ahead of Berkshire Hathaway's annual meeting to discuss the Federal Reserve, markets and more. "I think the market is fairly valued," Gabelli tells CNBC. "The bigger concern for me is the run off of the $9 trillion of the Fed and how quickly they are going to run it off, what impact it has on housing because you got to cool things down."