As the only COBOL expert available, I was asked to evaluate a performance problem reported by a customer who was attempting to convert their COBOL master file update program for use with ACMS XP. Examining the program and its use within the Encina toolkit made it clear that the customer program was implemented as a single thread of execution. Two problems became evident. One was that the design of ACMS XP required multiple threads of execution for maximum performance and the second problem was that the customer's program was implemented as a classic monolithic COBOL program. I improved the performance of the customer's program several fold by simply splitting the input file into several pieces and then modified the COBOL program to allow several instances of the program to run in parallel. The resulting performance exceeded the customer's previous performance cutting the execution time from 8 hours down to 2 hours.