BERLIN (Reuters) - Shares in the online fashion retailer About You AG made its market debut in the Frankfurt stock exchange on Wednesday, opening 11.3% above its offer price. About You opened at 25.6 euros per share, compared to the offer price of 23 euros apiece, valuing the German trading group at around 4 billion euros ($4.85 billion). About You, which operates in 23 European markets, competes with Zalando in the consumer segment while its B2B platform pits it against Shopify, SAP and Salesforce. The Hamburg-based startup reported 57% revenue growth to 1.17 billion euros in the year to February, and in the last quarter achieved its first positive core profit since its launch in 2014. The company is backed by mail-order group Otto and Danish tycoon Anders Holch Povlsen. Deutsche Bank, Goldman Sachs, and J.P. Morgan are acting as joint global coordinators and joint bookrunners, with Numis Securities, Société Générale and UBS Investment Bank also acting as Joint Bookrunners. ($1 = 0.8245 euros) Reporting by Riham Alkousaa; Editing by Caroline Copley Our Standards: The Thomson Reuters Trust Principles.