UBS helped housebuilders higher after it said that the positive fundamentals of the sector remain unchanged despite measures by the Bank of England announced yesterday to cool the housing market. It said that while a "policy over-reaction" is undoubtedly the biggest risk to the sector, this risk has already been largely priced into the market and that future intervention will be "gradual and measured". Taylor Wimpey was one of the bank's top picks.National Express rose on the news it has retained the Essex Thameside franchise for a further 15 years. The group, which currently occupies the line as c2c, will now operate the service until 2029. Meanwhile, Ophir Energy continued to dive after its 50%-owned Okala-1 well failed to find significant hydrocarbons in the target areas marking a disappointing end to its 2014 exploration campaign in Gabon.Shares in chip group Imagination Technologies dropped dramatically this morning after microprocessor giant Intel sold a 9.3% stake in the business.Chemicals group Alent fell on the back of negative readacross from a profit warning by US giant DuPont, one of the largest chemical companies in the world.FTSE 250 - RisersFoxtons Group (FOXT) 299.60p +5.87%Redrow (RDW) 282.10p +5.42%NMC Health (NMC) 494.50p +3.47%National Express Group (NEX) 255.40p +2.98%Taylor Wimpey (TW.) 112.90p +2.73%Berkeley Group Holdings (The) (BKG) 2,424.00p +2.71%Keller Group (KLR) 929.50p +2.71%Redefine International (RDI) 55.25p +2.70%Just Eat (JE.) 253.40p +2.59%ITE Group (ITE) 229.00p +2.55%FTSE 250 - FallersOphir Energy (OPHR) 217.50p -5.93%Imagination Technologies Group (IMG) 211.70p -5.83%Lonmin (LMI) 232.90p -3.20%Workspace Group (WKP) 575.50p -2.95%Debenhams (DEB) 66.30p -2.93%Alent (ALNT) 358.20p -2.61%Petra Diamonds Ltd.(DI) (PDL) 188.40p -2.48%RPC Group (RPC) 620.00p -2.21%Regus (RGU) 180.10p -2.12%International Personal Finance (IPF) 580.50p -2.11%NR