May 22 Reuters Mizuho Financial Group Inc will buy U.S. MA advisory firm Greenhill Co Inc for 550 million including debt, the companies said on Monday, as Japan39;s No. 3 lender eyes a bigger share of the world39;s largest investmentbanking fee pool.

Greenhill shares more than doubled to close at 14.66 on Monday after the announcement, just below the offer price of 15 per share.

Monday39;s boost helped Greenhill shares erase their losses accumulated over the last 12 months due to the impact of higher interest rates on dealmaking. The stock was priced at 20 in its 2004 initial public offering.

The Greenhill business will sit within Mizuho39;s banking division, led by Michal Katz, head of banking in the Americas. Its chairman and CEO, Scott Bok, will become chairman of the MA and restructuring advisory business.

We have a strong MA practice in Japan. But it39;s really early days here in the U.S. and in the other regions. So this is a way for us to scale in a meaningful way, Jerry Rizzieri, president and CEO of Mizuho Securities USA, told Reuters in an interview.

Mizuho has doubled down on U.S. debt underwriting since its 2015 acquisition of Royal Bank of Scotland39;s North American corporate loan portfolio, leaving MA advisory and equity underwriting as areas targeted for further growth.

Last year, it bought Texasbased private equity placement agent Capstone Partners.

Other Japanese banks have also been expanding their foothold in the United States.

Mizuho39;s…