AmEx’s shares fell 4.1 percent to $60.05 in extended trading on Thursday, after the company reported its fourth straight decline in total revenue, net of interest expense. Total revenue, net of interest expense, fell 7.6 percent to $8.39 billion. AmEx, which also operates payment networks, lost a few lucrative clients such as Fidelity Investments, retailer Costco Wholesale Corp (COST.O) and JetBlue Airways Corp (JBLU.O) last year.