An ACS spokesman said the letters sent out to 40 major suppliers to identify the prices they have charged different customers for the past five years was critical to the investigation (The Grocer, 4 November, p6).
The ACS believes suppliers charge wholesalers more for goods to compensate for the fact they are screwed down on price by supermarkets - known as the waterbed effect. "Manufacturers hold the source of the information that will either prove or disprove the case," he said. "We have evidence it exists and we have set it out to them."
The Competition Commission said it was close to completing its one-to-one hearings and was now awaiting supplier responses to the letter due at the end of the month.
Although the waterbed effect was not a phrase used internally by the inquiry team, according to a Commission spokesman, it wanted to hear how suppliers treated supermarkets and wholesalers differently in terms of prices. "We hear wholesalers are ordering in exactly the same quantities as some supermarkets, but they still don't get any better deals," he added.
The team has already visited some wholesaler depots and met the FWD.
The Commission said it planned to do all it could to stick to its timetable to publish emerging thinking before Christmas. "There is no reason to believe we won't complete this inquiry in less than two years."