Some of the world’s largest companies could save 10% to 20% of advertising costs with a systematic review of processes, according to Harish Hemmige, a principal in the Chicago office of the Boston Consulting Group.

The biggest companies can operate across 50-100 or more countries, and deal with 1,000 outside agencies. It seems almost certain that some inefficiency will creep in. But how do you harmonize the many parts? In this interview, Hemmige explains how largest firms tend to suffer from agency proliferation, rate creep and other inefficiencies that burn through cash that could otherwise fuel extra media buys.