Regulation has hurt revenue growth, but the flip side is it has dramatically reduced risk," he said. "So I'll take $1 of earnings today anytime over $1 of earnings before the financial crisis because the risk of those new earnings are a lot less."
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With the Federal Reserve poised to begin raising interest rates, perhaps sometime this year, bank stocks are the obvious beneficiary.
However, Mayo is still selective when it comes to picking stocks in the event that rates don't rise much.
He likes Citigroup, Morgan Stanley, Wells Fargo and JPMorgan.
"If those rates don't go up, those four bank stocks in particular still have extra earnings levers they can pull to accelerate earnings growth," he said.
Mayo is particularly bullish on Citigroup, which has not yet busted through its post-crisis high. He thinks it could double from current levels.
"Citigroup is knocking on the door. They would benefit from higher interest rates … but they are also a unique, global self-help story," he said.
"I've been following Citigroup for more than two decades. This is perhaps the best opportunity in those 20 years to own Citigroup, given the level of risk."
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However, while he thinks the financial industry is on firm footing because of strong balance sheets, good credit quality and more oversight by regulators, there is one issue that could derail things.
"The biggest issue to watch over the next five years or so is if interest rates go up too much, too quickly; that's the risk for the next financial crisis."
Disclosures: CLSA receives or has received compensation from Bank of NY Mellon and JPMorgan Chase for noninvestment banking services. Mayo or household members have a financial interest in the securities of Citigroup, KeyCorp, Morgan Stanley and State Street.