Citigroup needs to do "whatever it takes" to cut costs to meet its efficiency target for the year, Wells Fargo analyst Mike Mayo told CNBC on Friday.
The bank recently warned it will likely fall short of its 2018 efficiency target, an outcome Mayo said is "not OK."
"I can't believe that this is happening at Citigroup of all companies," he said on "Fast Money: Halftime Report."
Instead of the stated target of a 100-basis-point improvement in operating efficiency year over year, Citi "could end up in the 90 basis points, maybe a little bit better range," Citi CFO John Gerspach said at the Goldman Sachs U.S. Financial Services Conference on Wednesday.
Gerspach blamed the shortfall on "much tougher" conditions this quarter, thanks to the recent market volatility.
Mayo said the shortfall equates to $70 million of additional expenses.
"They should find $70 million of expense savings before the end of year," he said. "Maybe that means reducing compensation, reducing the number of Ubers that they use, reducing travel, reducing holiday parties."
He wants CEO Michael Corbat to override the CFO and find those savings.
In fact, the bonuses of the top five Citi execs last year totaled $70 million, Mayo said.
"You can reduce the bonus of the top five executives or you can reduce the bonus of the top 25 executives by 20 percent," he said.
Citigroup declined to comment on Mayo's remarks.
Disclosures: Mayo owns shares of Citi and Wells Fargo expects to be paid for investment banking services from Citigroup.