SunTrust Robinson Humphrey, the corporate and investment banking arm of the Atlanta lender, is focusing on businesses in the three cities with annual revenues between $100 million and $5 billion, Mark Chancy, SunTrust's head of wholesale banking said in an interview.

The bank is hoping that as rivals have pulled back from lending to mid-sized companies, it will be able to win market share, Chancy said.

Chancy said the three cities were chosen because they are home to a large number of mid-sized companies in fast-growing industries, such as energy in the case of Texas and information technology in the case of San Francisco. SunTrust plans to offer traditional banking services including deposit-taking, lending, and treasury management. As the companies grow, the bank can also offer investment banking services like stock and bond underwriting, Chancy said.

SunTrust is looking to staff the Dallas, San Francisco and Chicago corporate banking offices with between 10 and 20 professionals. Additionally, it is looking at another three to five U.S. cities as the next candidates for expansion.

Around 40 percent of the Atlanta bank's revenue comes from wholesale banking, a division that includes SunTrust Robinson Humphrey, and growth there helped offset a slowdown in mortgage banking in the second quarter. The corporate and investment bank has grown at a compound annual rate of 15 percent in the last few years and has "a lot of really good momentum continuing in that business," chief financial officer Aleem Gillani told analysts on an October 18 conference call.

SunTrust is the 13th largest U.S. bank with total assets of $171.8 billion. Its shares have risen 18 percent since the start of 2013, lagging the 25 percent increase in the KBW index of bank stocks <.BKX> over the same period.

(Editing by Bob Burgdorfer)

By Peter Rudegeair