One of the co-founders of group purchasing holding company Omnia Partners will step down from the Cool Springs-based company at the end of this year.

Ward Brown launched what was then called Horizon Resource Group with Todd Abner in 2001 to focus on group purchasing for the higher education sector. He has since overseen its operations and growth, which included the 2006 creation of National Intergovernmental Purchasing Alliance, the 2013 merger with a unit of Vizient and the formation three years ago of the Omnia holding company.