American Express Co has for several years quietly been building a major computer services business, and now believes it’s time to go public on it. It has therefore announced the formation of American Express Information Services Co, and aims to compete with Electronic Data Systems and Automatic Data Processing Inc. The new unit starts life with profits running at $63m on turnover of $446.9m, and will offer funds transfer, billing, accounts processing and other bureau and transmission services, and will take in the Shareholders Services Group owned by AmEx’s Boston Group subsidiary.