Shares in Connaught have fallen sharply on news Mark Tincknell will step down as executive chairman and take on the role of chief executive of the social housing firm to replace Mark Davies, it announced today.Davies originally planed to leave the company at the end of the current financial year to seek new challenges elsewhere, but Connaught decided to appoint Tincknell as his replacement from 1 February in order to ensure strategic continuity and clear leadership. Retailers are among the fallers, with Sports Direct and Currys and PC World owner DSG International in the red, joined lower by housebuilders Barratt and Bovis Homes.FTSE 250 - RisersGem Diamonds (GEMD) 235.30p +5.99%Computacenter (CCC) 307.00p +5.83%Rightmove (RMV) 530.00p +5.79%Ecofin Water & Power Opportunities (ECWO) 139.90p +5.11%BBA Aviation (BBA) 164.60p +4.18%Yell Group (YELL) 36.61p +4.15%Informa (INF) 329.70p +3.91%Keller Group (KLR) 631.00p +3.78%Shanks Group (SKS) 125.80p +3.54%JPMorgan Indian Inv Trust (JII) 365.50p +3.28%FTSE 250 - FallersConnaught (CNT) 327.30p -9.06%Sports Direct International (SPD) 96.40p -3.60%DSG International (DSGI) 31.27p -3.46%Laird (LRD) 123.80p -2.90%Aberdeen Asset Management (ADN) 123.50p -2.14%Bovis Homes Group (BVS) 400.00p -2.13%Homeserve (HSV) 1,636.00p -2.09%PV Crystalox Solar (PVCS) 56.90p -1.90%Aquarius Platinum Ltd. (AQP) 371.30p -1.72%Barratt Developments (BDEV) 119.10p -1.65%