The operating loss before amortization (Ebit) increased to €92 million for Zalando in 2012 compared with €61.2 million in the previous year. However, as a percentage of sales, the operating margin improved from a negative ratio of 12 percent to a negative ratio of 8 percent as the online retailer's sales grew by 125 percent to €1.15 billion, breaking the €1 billion hurdle after only four years in business.

The losses were mostly due to high investments in logistics, infrastructure and information technology, expanded product ranges, and the internationalization of the business. The number of countries where Zalando is operating in Europe doubled from seven to 14 in the course of last year.

The company is already breaking even in the German-speaking countries, which account for well over half of the total turnover. Footwear now represents almost half of sales, but apparel is growing strongly and has potential for further growth. Private label represents less than 5 percent of the turnover.

As previously reported, Rocket Internet, Kinnevik, Tengelmann, JP Morgan and other shareholders have injected more than €600 million in equity into Zalando. The company's debt-equity ratio stands at more than 50 percent.