Hospitality company Carlson, which owns such familiar brands as Radisson Hotels, T.G.I. Friday's and the Carlson Wagonlit business travel service, is reaping vast savings with its new telecom expense management (TEM) provider, whose services go beyond the standard approach of identifying carrier overbilling.

According to a recently published Gartner research note, companies that outsource TEM for their fixed lines could save from 16% to 32% of overall fixed-line spending in the first two years, and from 5% to 11% in subsequent years, by avoiding costs, recapturing overpayments and staff reductions. If a company would rather implement TEM as a managed service, those returns drop to a 4% to 15% savings in the first two years, followed by annual savings of between 4% and 8%.

"Identifying overbilling is the raison d'être for TEM," says Phil McDonald, director of sourcing operations at Carlson, which had $5.4 billion in 2011 revenue. "Carriers are notorious [for] invoicing incorrectly."