Well-known investors, buy-and-hold specialist Mario Gabelli and short seller Douglas Kass, duked it out over Warren Buffett's Berkshire Hathaway on CNBC Friday from CenturyLink Center Omaha Arena, where Saturday's annual shareholders meeting will take place.
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In a "Squawk Box" interview, Kass, head of Seabreeze Partners Management, detailed his short position in Berkshire B shares. "This is the second time I've shorted it. I've been short it about a month and a half at an average cost of about $104.38, the B stock, a couple bucks underwater."
While Kass admitted that he's had a long position in Berkshire at times over the years, his other short bet on the stock was in March of 2008. "The stock subsequently fell by 40 percent so I did well that time," he said.
Kass will be on stage Saturday asking questions of Buffett and Berkshire vice chairman Charlie Munger. Kass said he did extensive research in preparation, but refused in Friday's CNBC interview to lay out his short thesis beforehand.
Meanwhile, Mario Gabelli made his case for why he's bullish on Berkshire stock. "We started buying it when I started a Gabelli mutual fund, the Gabelli Asset Fund, in 1985. Still own it."
He said the Berkshire A shares cost him $3,000 each at the time and they're currently trading at more than $160,000 a share. He explained that he sees further upside in the stock and said it doesn't make sense to incur the expense of buying, selling, and re-buying stocks you like.—By CNBC's Matthew J. Belvedere. Follow him on Twitter @Matt_SquawkCNBC.