FILE PHOTO: The Citigroup Inc (Citi) logo is seen at the SIBOS banking and financial conference in Toronto, Ontario, Canada October 19, 2017. REUTERS/Chris Helgren

(Reuters) - Citigroup Inc C.N is laying the foundation, through a growing network of mobile banking tools, to support the launch of a national digital consumer bank sometime within the next three years, its chief financial officer said on Tuesday.

“I am not making an announcement right now, but I would be really disappointed if it was anything close to being three years away,” CFO John Gerspach said at an investor conference. “We really are laying the groundwork for having a national digital bank.”

Gerspach also said first quarter markets revenue was up by a “low-to-mid” single digit percentage from a strong quarter a year earlier.

Citigroup operates branch offices for individuals in only six big U.S. cities, but has a national franchise in consumer credit cards. After the 2007-2009 financial crisis, it retreated from offices in smaller cities and the state of Texas to reduce costs.

Gerspach said the bank does not want to begin marketing a national digital bank to consumers until it is sure it can digitally open and service accounts over mobile phones and computers to the satisfaction of customers.

The banking industry has been pruning branch networks as people increasingly use smartphones to make deposits and payments. But industry expert say having branches still makes it easier to attract new accounts.

Citigroup, the fourth-biggest U.S. bank by assets, had fewer than 700 U.S. branches at year-end compared with more than 4,000 at the three biggest banks, JPMorgan Chase & Co, JPM.N Bank of America Corp BAC.N and Wells Fargo & Co. WFC.N

Gerspach's outlook for market revenue comes one week after a JPMorgan Chase & Co JPM.N executive said first quarter markets revenue was increasing by a "mid-to-high" single digit percentage from a strong quarter a year earlier.

Executives at both banks said revenue was particularly strong in foreign exchange, emerging markets and equities trading.