BMO Financial Group, the Canadian banking giant that has a growing Midwest foothold, is buying the Minneapolis investment bank Greene Holcomb Fisher, the companies said Thursday.

The transaction, terms of which were not released, is expected to close this fall, pending regulatory approvals.

“Greene Holcomb complements our strategy as we build the business in the U.S.,” Peter Myers, BMO’s head of investment and corporate banking, said in an interview Thursday in Minneapolis. “It gives us deeper capabilities and adds [Midwest and national] geographic focus.”

Hunt Greene founded “GHF” in 1995 with Brian Holcomb after they left the investment banking group of Piper Jaffray. Their firm will take the name and integrate into BMO Capital Markets through a new Minneapolis office.

Greene said Thursday that he and nine other partners, the owners, will remain after the cash deal closes. Greene added that the firm was not actively being auctioned. However, Greene listened when BMO came courting with a good offer and bigger future for the firm and its employees.

GHF is a boutique investment bank that mostly represents sellers. The firm has completed more than 100 transactions since 2011, including 32 last year, its best, with deals valued at more than $3 billion. It has doubled employment to 32 investment bankers over the last five years.

“We’ve been growing fairly quickly and adding people,” Greene said. “This creates a career path for our people and we hook up with somebody with a broader reach, and BMO Capital Markets is in the industries we are in. People in our industry always have trepidation about going to work for a big bank. But this is not a clash of cultures with their capital markets group. It was a way for them to take this platform to the next level.”

Greene Holcomb Fisher targets the “middle market,” an area that BMO has been focusing on in the United States.

The firm typically represents sellers with revenue of less than $500 million and median deal values of around $100 million. Greene Holcomb Fisher also has offices in Seattle and Atlanta.

BMO’s capital markets division expanded aggressively in the United States since the financial crisis, amid weakened U.S. competition hurt by the mortgage debacle.

Other Canadian banks active in the U.S. include Royal Bank of Canada, which has its U.S.-based wealth management business based in Minneapolis, and Toronto Dominion Bank.

Greene Holcomb Fisher recently represented family-owned Mills Fleet Farm, a home and farm products retailer, in its sale to New York investment firm KKR for a reported $1.2 billion. It was the biggest deal the bank had ever negotiated.

Mills, founded in the 1950s, attracted several potential buyers in a market fueled by low interest rates and abundant capital.

In 2014, Greene Holcomb Fisher negotiated the sale of privately held Bergquist Co., a Chanhassen-based maker of insulating materials for electronics products, for $570 million to German industrial conglomerate Henkel.

Greene, 65, a Harvard MBA from Texas with a low-gloss approach, worked 20 years for Piper Jaffray before starting the investment bank. Holcomb, 59, also was a Piper Jaffray veteran.

BMO’s capital markets group employs 2,300. Its Toronto-based parent company, formerly known as Bank of Montreal, boasts North American assets of $681 billion and 45,000 employees. BMO has grown its commercial and consumer banking business in Minnesota in recent years. It long has been considered a possible suitor of Twin Cities-based TCF Financial.