Mentzer Software Engineering GmbH is a Swiss software company based in St. Gallen. It develops business applications and tools for organizations in manufacturing, banking, and software development, with solutions designed to support structured, integrated workflows.

For smaller and medium-sized manufacturing businesses, its industrial production planning system manages materials across the process, from preparing quotations through debtor control. The system also supports quality assurance in line with ISO 9000.

For banks and wealth managers, Mentzer offers Modern Portfolio Management, an application for handling business transactions and investment types consistently within a single system. Its functions include maintaining customer positions, reporting performance, preparing integrated profit-and-loss statements, defining investment groups, and reviewing asset allocation. The software can manage multiple clients and any number of customers.

The company also provides software methods and tools for creating database applications. These offer end-to-end tool support for generating client-server applications for Windows and Oracle environments. Mentzer Software Engineering lists partners in the banking and software sectors and provides contact details at its St. Gallen address.