Firstar, which merged with Mercantile Bancorp Sept. 20, announced it will combine the asset management subsidiaries of each company into a single entity. Firstar Investment Research & Management and Mississippi Valley Advisors will merge early next year under the FIRMCO name, said Mary Ellen Stanek, president and CEO. Firstars investment management division will maintain offices in Milwaukee and St. Louis, with the latter headed by John Blixen, now president and chief investment officer of MVA. Titles for all employees are being reviewed and will be standardized, Ms. Stanek said. FIRMCOs assets under management totaled $25.1 billion (50% institutional) and MVAs totaled $9.5 billion (80% institutional) as of Sept. 30.