Mayo: BofA too big to succeed

• "There is evidence of diseconomies of scale," writes longtime Bank of America (BAC -0.6%) bear Mike Mayo, arguing the lender would be worth 25% more if broken up.
• "We do not see the downside for investors in supporting greater transparency," says Mayo, applauding the SEC's forcing the bank to allow a vote on a proposal calling for the spinoff of its investment banking operation.
• Mayo notes recent accountability issues like BofA being the only U.S. lender called out by the Fed in its stress tests this year, and last year's $4B accounting boner, after which the bank was forced to suspend its capital return plans.