A defensible price comparison begins with the price history. For each item and each channel, the price actually applied on each day should be verifiable. Point-of-sale systems, shop databases, marketplace logs and screenshots of promotional states form the underlying dataset. From this data the lowest price of the preceding 30 days can be derived automatically and recorded for the moment when a reduction is announced.
The file is completed by a channel log, promotion plan, approval steps and marketing versions. Where an internal price list, a landing page and a search advertisement are used, the version, responsible person and approval date should be recorded. For progressive reductions the starting value before the first announcement and the sequence of markdown steps must be documented separately so the overall impression can be explained later.
After a challenge, preserve the complete letter, service date and every advertising version mentioned. The article on a UWG cease and desist letter from a competitor or association covers the separate assessment of claim, undertaking and evidence. For possible interim relief, the topic on injunctions and interim relief maps risk of repetition and protective objective.