TOKYO (Reuters) - Sumitomo Mitsui Financial Group Inc's (>> Sumitomo Mitsui Financial Group, Inc.) brokerage unit is ready to poach bankers to expand its U.S. investment banking arm and could even buy small firms if the right target comes up, its chief executive said.

SMBC Nikko, Japan's third-biggest brokerage by assets, launched in New York last year a niche team focusing on mergers and acquisitions (M&A) and debt capital markets in an effort to capitalize on Japanese companies expanding in the United States.

"If targets come up for sale, we have the strength to buy them," Yoshihiko Shimizu said in an interview. "But if we do buy something, it would be as much as a team (of bankers)."

"If that one team is a company, we'll buy the whole company. If there are 30 able people in a team of 100, I only want the 30 people," he said.

Japanese investment banks and brokerages are betting on the U.S. as domestic companies strive to escape a shrinking population and tepid growth at home by expanding in the world's largest economy.

SMBC Nikko's rivals Nomura Holdings Inc (>> Nomura Holdings Inc) and Daiwa Securities Group Inc (>> Daiwa Securities Group Inc), Japan's biggest and second-biggest brokerages respectively, have this year beefed up their U.S. investment banking coverage.

Nomura is boosting its ranks of investment bankers in New York, including senior hires in the tech and finance sectors. Daiwa, looking to earn more money from advising mid-sized firms, bought two boutique M&A advisory firms in New York and Baltimore.

Still, Shimizu said buying large securities firms could risk a loss of control - something that has hit Japanese brokerages before. Nomura's 2008 acquisition of Lehman Brothers' Asian and European businesses led to six straight years of overseas pretax losses totaling 385 billion yen ($3.40 billion).

SMBC Nikko's New York team, comprising 10 senior bankers, focuses on sectors where the brokerage's parent - No. 3 among Japan's "megabanks" - has strong connections, including pharmaceuticals and raw materials.

In the year to November, the parent was the top advisor by number of deals involving Japanese firms, but only fifth by deal volume, Thomson Reuters data showed. Last year it ranked second by commissions and 10th by deal volume.

"Little by little, we're seeing success." said Shimizu, a 39-year veteran of Japan's banking industry.

SMBC Nikko will leverage its parent's lending business as an "entrance ticket" to broaden opportunities in debt and equity financing and M&A advisory, Shimizu said, with the company looking to serve major Japanese firms.

"You can't make money by focusing only on blue-chips. But at the same time I don't want to focus in America on small and medium-size firms," he said.

(Reporting by Thomas Wilson and Takahiko Wada; Additional reporting by Taro Fuse; Editing by Christopher Cushing)

By Thomas Wilson and Takahiko Wada