Polymetal received a boost from Canaccord Genuity which raised the stock to 'buy' after lifting its assumptions for gold prices over the medium and long term.Kenmare Resources was recovering well after it last week posted losses of $44m for 2013, helped by positive comments from both Goodbody Stockbrokers and Canaccord Genuity later on. Housebuilders including Grainger, Bovis Homes, Taylor Wimpey, Crest Nicholson and were making gains after UK Chancellor George Osborne announced that he is extending the 'Help to Buy' mortgage guarantee scheme by a further four years. Investors were also responding to Rightmove data which showed that asking prices for homes in the UK rose by 1.6% month-on-month in March to hit a new record high of £255,962.Micro Focus rose after Barclays upgraded the stock to 'overweight', with a target price of 900p.Maarten Slendebroek has taken over as Chief Executive Officer of Jupiter Fund Management on Monday. He succeeds Edward BonhamCarter, who will remain on the board and work as Vice Chairman. Bonham Carter led Juipter's buyout from German group Commerzbank in 2007 and its stock market float three years later in 2010.Meanwhile, Essar Energy fell after it was revealed it had rejected an offer put forward by Essar Global Fund, which already owns 78.02% of the group. The group said the 70p-a-share offer undervalued the company. bwin.party was in the red after Citi cut its target price from 125p to 95p and downgraded the stock from 'neutral' to 'sell'.Oil and gas production firm Cairn Energy was lower after it revealed that one of its exploration wells offshore Morocco has been plugged and abandoned without testing. Drilling of the JM-1 well, located in the Juby Maritime blocks, started in January to evaluate Upper Jurassic and Middle Jurassic objectives.FTSE 250 - RisersKenmare Resources (KMR) 14.85p +9.19%Polymetal International (POLY) 610.00p +7.11%Bovis Homes Group (BVS) 896.00p +4.80%Crest Nicholson Holdings (CRST) 380.20p +4.11%Micro Focus International (MCRO) 804.50p +3.94%Grainger (GRI) 239.50p +3.81%TalkTalk Telecom Group (TALK) 312.40p +3.72%Inmarsat (ISAT) 699.00p +3.63%SEGRO (SGRO) 346.40p +3.13%Workspace Group (WKP) 575.00p +3.05%FTSE 250 - FallersEssar Energy (ESSR) 64.25p -3.46%Genus (GNS) 1,052.00p -3.22%Kazakhmys (KAZ) 257.60p -2.42%CSR (CSR) 722.00p -1.70%Bwin.party Digital Entertainment (BPTY) 123.30p -1.67%Cairn Energy (CNE) 193.70p -1.63%Synthomer (SYNT) 261.40p -1.32%Imagination Technologies Group (IMG) 160.70p -1.29%ITE Group (ITE) 221.00p -1.21%Greencore Group (GNC) 264.70p -1.08%NR