Citigroup shares have jumped 11.3 percent in the past three months, but they're still a bargain, despite the $600 million charge the country's third-largest bank announced Thursday for legal expenses, says CLSA bank analyst Mike Mayo.

He still sees Citi's profit doubling in the next four years, CNBC reports.

"It's been 16 days since Citi reported third-quarter results. In 16 days, they came up with another $600 million write-down," he tells the network.

"And so, it's like oh no, not again. Citigroup needs to stay out of the headlines. Having said that, it's like what you would say to your kids when they're acting badly. 'I don't like what you did, but I still love you.' I don't like seeing a $600 million write-down, but I still love Citigroup stock," Mayo notes.

"They need to have day after day after day that's uneventful," he adds. "Citigroup needs to become boring. Having said that, this is not life-threatening. The hit to book value is one-third of 1 percent, and Citigroup remains, what I think, the best restructuring story among global banks."

The shares, which closed at $53.47 Monday are still undervalued, Mayo says. "In the theme of Halloween, it's like free candy at these prices." He rates the stock a "buy" and has a price target of $107.

Morningstar analyst Jim Sinegal isn't quite so enthusiastic.

"While this does not materially affect our fair value estimate for the bank [$48 a share], it does reinforce our thesis that elevated legal and regulatory costs will continue to plague the nation's largest banks for the foreseeable future," he writes on Morningstar.

"These costs, in addition to creating uncertainty around the timing of interest rate changes, limit our near-term enthusiasm for the bank."

Related Stories:

• Citi Slashes Profit by $600 Million as Probe Costs Mount
• Citi Pulls Consumer Banks From 11 Markets, Posts Higher Profit