CNBC's Jim Cramer called Wells Fargo a "rogue bank" on Thursday after the bank said it uncovered much more potentially unauthorized consumer and small-business accounts than originally thought.
On Thursday, Wells Fargo said its review of 165 million retail accounts opened from January 2009 to September 2016 identified 3.5 million as potentially unauthorized, up from 2.1 million accounts identified in a narrower review.
"A million extra? I mean that's not a rounding error," Cramer said on "Squawk on the Street." "It's not embarrassing, it's rogue. This is a rogue bank."
Perhaps Sen. Elizabeth Warren, who has been tough on Wells Fargo, had a point, added Cramer. In June, the Massachusetts Democrat called for the ouster of 12 board members at Wells Fargo due to the fake accounts scandal.
"They thought they got to the bottom of it but they left out a million accounts," Cramer said. "That does not seem like the bottom of this. This is so outrageous."
"I'd like to call all those board members to Congress," he added. "This was a bank that ran amok in order to meet cross-selling obligations. ... We should not let up on this Wells Fargo situation."
"What you find is there's never just one cockroach in the kitchen when you start looking around," the chairman and CEO of Berkshire Hathaway said on "Squawk Alley." Berkshire is Wells Fargo's largest shareholder.
In response to Buffett's comment, a Wells Fargo spokesperson said in part: "Our top priority is rebuilding the trust of our customers, team members, community partners, and shareholders."
CNBC has reached to Wells Fargo for further comment but the company did not immediately respond.
— CNBC's Liz Moyer contributed to this report.