Doug Kass, Still a Berkshire Bear

A noted bear on Warren Buffett's Berkshire Hathaway, Doug Kass said Monday that he remained negative on the company after facing off at with the Oracle of Omaha over the weekend.

"I feel as strongly as I did before," he said on CNBC's "Fast Money."

"The stock was up actually only about 1 percent on a very strong insurance tape, despite better-than-expected numbers after the close on Friday, which benefited from low catastrophic experiences in their insurance line and a lot of investment gains," he added.

Berkshire Hathaway class A shares closed at $164,990, up $ 2,086.00, or 1.28 percent.

Kass, head of Seabreeze Partners Management, had been invited to present the bear case at Berkshire Hathaway's annual shareholder meeting in Omaha, which he likened to going to the "Woodstock of capitalism." Arguing the bull case was Buffett.

(Read More: How Doug Kass Became Buffett's Bear)

Asked whether he saw any other companies so intertwined with their iconic leaders, such as JPMorgan Chase and its CEO Jamie Dimon, Kass said that wasn't the case.

"Jamie doesn't pull the strings that Warren does," he said.

Kass was also asked whether he thought the company would be likely to negotiate preferred stock pricing without its 82-year-old chief executive.

"That was one of my questions, whether with him gone and the loss of the Buffett imprimatur, would he be able to get those deals?" Kass said. "His response was basically that, yes, I will be gone, but replacing my persona will be a huge amount of capital, and we will continue to be able to buy things very quickly. I'm not exactly sure if I agree with that."

(Read More: Buffett's Berkshire Stock: 'Bull' Gabelli vs. 'Bear' Kass)

Kass also declined to answer whether he thought the stock rally would continue.

"I don't know. I've been bearish since January," he said. "I'm a bad person to ask."

Trader disclosure: On May 6, 2013, the following stocks and commodities mentioned or intended to be mentioned on CNBC's "Fast Money" were owned by the "Fast Money" traders: Guy Adami is long C; Guy Adami is long GS; Guy Adami is long INTC; Guy Adami is long AGU; Guy Adami is long MSFT; Guy Adami is long NUE; Guy Adami is long BTU; Steve Grasso is long AAPL; Steve Grasso is long ASTM; Steve Grasso is long BA; Steve Grasso is long BAC; Steve Grasso is long GDX; Steve Grasso is long GOOG; Steve Grasso is long LF; Steve Grasso is long LNG; Steve Grasso is long MHY; Steve Grasso is long MJNA; Steve Grasso is long PXD; Steve Grasso is long NVIV; Steve Grasso is long PFE; Steve Grasso is long S; Steve Grasso is funds long AAPL; Steve Grasso is funds long EMC; Steve Grasso is funds long HA; Steve Grasso is funds long MSFT; Steve Grasso is funds long OXY; Steve Grasso is funds long HPQ; Steve Grasso is funds long NEM; Steve Grasso is funds long ZNGA; Brian Kelly is long TREASURY FUTURES; Brian Kelly is long CORN; Brian Kelly is long WHEAT; Brian Kelly is long SOY; Brian Kelly is long JJG; Brian Kelly is long EWZ; Brian Kelly is long EWW; Brian Kelly is short OIL; Dan Nathan is long BBRY JUNE/JULY 14 PUT SPREAD; Dan Nathan is long IBM JUNE 205/295/285 PUT FLY; Dan Nathan is long CSCO MAY 21 STRADDLE.