Michael Sharp, the Executive Director of retail chain Debenhams, has topped up his stake in the group with the purchase of 50,000 shares. Sharp, who has been in his current role since September 2011, bought the shares at 97.20p for a total of £48,598. He now holds 6.2m shares in the company.Debenhams last month reported a strong end to 2012 including record levels of sales in December, but said heavy discounting had hit margins. In the 18 weeks to 5th January, total sales values increased by 3.5%, while like-for-like sales grew by 2.9%. Over the five weeks to the same date, like-for-like sales increased by 5.0% compared to the year before and by 8.5% on 2010. However, the firm said margins took a battering as customers looking for bargains ahead of Christmas as well as in the traditional sale period, and warned that it now expects gross margin for the year to be 10 basis points higher than last year rather than 20 basis points as previously guided. Top Director SellsCarr's Milling Industries (CRM) Director name: Mr Christopher HolmesAmount sold: 2,250 @ 1,079.00p Value: £24,278e-Therapeutics (ETX) Director name: Mr Malcolm YoungAmount sold: 50,000 @ 31.00p Value: £15,500