HSBC said in May that it was exploring a possible sale of the unit.
Capital One said Wednesday that the deal should provide a significant boost to its 2013 operating earnings and help raise about $1.25 billion in capital.
The McLean, Va.-based bank says the acquisition will result in about $350 million in cost savings. It will also incur approximately $420 million in restructuring costs tied to the deal.
The acquisition is expected to close in the second quarter of 2012.