Leading Japanese retailer Fast Retailing Co, owner of the famous Uniqlo casual-clothing store chain, said on Friday its same-store sales plunged 35.2 per cent in January from the year-ago period. The slide comes shortly after the firm bought back nearly $90 million worth of its own shares in a bid to stop its plummeting share price, posted a 17 per cent fall in same-store December sales and slashed its earnings forecast for the year to August by more than 30 per cent.