The San Francisco African American Chamber of Commerce has told banking regulators that it opposes Union Bank’s $1.5 billion acquisition of Santa Barbara-based Pacific Capital Bancorp, according to the business newspaper for that region.

The San Francisco Business Times reports that the chamber has told regulators it opposed the deal because it feels San Francisco-based Union Bank has not done enough to support the Bay Area’s African American business community. Big bank mergers often prove to be an opportunity for minority groups to leverage regulators to gain concessions from the institutions.

The Pacific Coast Business Times could not immediately reach Pacific Capital, parent of Santa Barbara Bank & Trust, for comment on Friday.

When the deal was announced in March, Union Bank made an effort to stress its community involvement and philanthropic efforts, saying that it would continue to support the organizations that Santa Barbara Bank & Trust has historically backed, and that the Community Partners Center on Cabrillo Street in downtown Santa Barbara would remain as a free meeting space for nonprofits. The $1.5 billion deal is by far the largest banking transaction in the history of the Tri-Counties.

In press materials, Union noted that it gave away $11.2 million in charitable contributions last year. Union Bank parent company UnionBanCal has assets of nearly $90 billion and is a unit of Mitsubishi UFJ Financial Group, based in Japan.

Pending regulatory and shareholder approval, the Pacific Capital acquisition is expected to close by the end of this year, rebranding all Santa Barbara Bank & Trust branches to Union Bank.