 ASOS PLC LON:ASC shares have fallen so much this morning that the online retailer has almost been knocked off its throne as the junior markets largest company. Shares in the owner of the Topshop, Topman, Miss Selfridge and HIIT brands have tumbled 16 this morning to below 40 for the first time since August last year on the back of a trading update that revealed good sales growth but a squeeze on profit margins from rising freight costs and a slowing of UK growth in the final weeks of June. 