Macquarie Group overnight said it agreed to buy US investment bank Fox-Pitt Kelton Cochran Caronia Waller LLC for about US$130 million, along with assumed debt of US $17 million.Private equity firm JC Flowers is the vendor.Fox-Pitt is a niche equity underwriter and has a growing team of equity research analysts.Macquarie has made two other North American investments this year. In May it bought Tristone Capital, an energy and resources investment bank, in Canada. Last month it agreed to buy Lincoln National's asset-management business.