Symbol group is a mainly British term for a form of franchise in the retail sector. They do not own or operate stores, but act as suppliers to independent grocers and small supermarkets and produce stores which then trade under a common banner. Unlike other forms of franchise, they have expanded primarily by selling their services to existing stores, rather than by actively developing new outlets. SPAR is a well known symbol group with stores in many countries. There are several smaller symbol groups in the United Kingdom, such as Londis, Costcutter, Premier Stores and Nisa-Today's.
In 2009, IDG reported that the symbol group market is worth £10.4bn, with a 35.9% share of the UK convenience market and a 7.3% share of the total UK grocery market.
IDG report: http://www.igd.com/index.asp?id=1&fid=1&sid=7&tid=26&cid=108