 Zalando, the German online fashion retailer, sent shares in UK rivals boohoo and ASOS tumbling after a warning that it is no longer benefitting from rebounding consumer confidence. Guidance for the fiscal year was cut by Zalando, with revenue now expected to grow anywhere between 0 and 3 to 8.92bn- 9.18bn, compared to predictions earlier in the year of 12 to 19 growth. 