Although designed and initially marketed by IBM primarily for engineering and scientific work, the IBM 650 also proved to be very successful in business applications. The following is a listing of some of the nearly 2,000 customers -- both businesses and scientific/technical users (noted with an asterisk) -- who acquired IBM 650s in the 1950s. (By April 1956, there were already 212 IBM 650s installed in customer locations, with an additional 18 installed in IBM facilities, while another 873 machines were on order but not yet delivered.)

The date shown in some of the entries below is the initial customer delivery date. The figure in parentheses in some of the entries indicates the total number of 650s installed by that customer as of 1956; the absence of such a notation indicates a single 650 installation. In some cases, there are no data identifying the U.S. city and/or state of the installation.