The Discount Comes Last: An Operator's Guide to Margin-Aware Promotion Routing in Premium Apparel and Footwear E-Commerce

A practitioner working note synthesising causal targeting, inventory economics, promotion design and EU consumer-law guidance into an operating policy for premium apparel and footwear e-commerce. No new empirical results are reported. The note assembles five established results — incremental-response targeting, response-dependent incentive costs, the shadow price of seasonal inventory, the delayed cost of promotion, and the EU disclosure and reference-price regime — into a single routing rule: which intervention, if any, a given visitor should receive on a given SKU, with price reduction positioned as the last lever rather than the first. It specifies a phased, deterministic-first implementation, a test protocol that addresses shared-inventory interference, and the limits of the current legal reading. A compiling reference implementation of the phase-one eligibility rules is included as a supplementary file. Version 1.0. Not peer reviewed. Nothing in this note is legal advice.