The top share index is holding onto its gains, continuing to sit near 2½-year highs.There has been some big economic news, but the market was largely unmoved. Third quarter UK gross domestic product (GDP) rose 0.7%, revised figures show. Previously third quarter GDP growth had been estimated at 0.8%.Meanwhile, the minutes from the December meeting of the Bank of England's monetary policy committee (MPC) revealed that the committee was once again split three ways on what to do about interest rates and quantitative easing (QE). For the seventh month in a row MPC member Andrew Sentance voted for a rise in interest rates, while Adam Posen repeated last month's call for a £50bn boost to the Bank of England's QE programme.ARM Holdings is a notable riser, with the chip designer's shares up 10%. Software giant Microsoft is expected to announce a new operating system for hand-held touch screen computers that would use ARM's technology. FTSE 250-listed peer CSR is up in sympathy.BSkyB is higher following news that business secretary Vince Cable has been stripped of his power to rule on News Corporation's takeover of BSkyB after telling undercover reporters he had "declared war on Rupert Murdoch". Cable kept his job on the insistence of LibDem leader Nick Clegg, but David Cameron called Cable's comments "totally unacceptable and inappropriate". Cruise operator Carnival is enjoying a second day of gains after yesterday's fourth quarter results.British Land and Oxford Properties, the real-estate arm of Ontario Municipal Employees Retirement System (Omers) pension fund, have put pen to paper and signed contracts for a 50:50 joint venture to develop a new skyscraper in the heart of the City. The company, which mothballed the project during the recession, said the 736 ft (224m) 'Cheesegrater' is already generating strong interest from insurance and financial companies, and professional and corporate business sectors. It wil cost £340m and should be finished by the middle of 2014. Underwriter Catlin has raised the amount it expects to lose due to the New Zealand earthquake in September by US$10m (£6.5m) to $45m. The company said it was making the announcement 'in view of the increased interest in this event by the investment community.' The earthquake, which was in the Christchurch area, was estimated to have damaged about two thirds of the 160,000 homes there. Construction and engineering group Costain has emerged as one of the companies that has made an approach to struggling support services group Mouchel, sending the latter's shares higher. Costain announced today that it approached Mouchel's board on 2 December, with a view to making an offer comprising 0.5135 Costain shares for every Mouchel one, valuing Mouchel at 105.8p based on Costain's closing price yesterday. Sticking with the takeovers theme, shares in food producer Northern Foods were selling like hot-cakes after it confirmed that it had received an approach from Boporan Holdings, controlled by the owner of the Harry Ramsdens chip shop chain Ranjit Boparan. Northern added that it remains committed to its proposed merger with the Irish food group Greencore.Shares of Newmark Security plummeted after it said first half pre-tax profit more than halved but it remains optimistic for a better second half.Computer products developer Concurrent Technologies said sales in the second half of the year are expected to 'materially exceed' sales in the first as the recovery in the telecommunications and industrial sectors gains momentum.News that it has signed two new contracts with Deutsche Telekom and defence contractor QinetiQ were cited by Imaginatik's chairman, Matt Cooper, as "evidence of the growing sales momentum" at the software firm, and the market seems to be in agreement, as the shares shot up in early trading.FTSE 100 - RisersARM Holdings (ARM) 437.50p +8.43%Carnival (CCL) 3,001.00p +3.30%Severn Trent (SVT) 1,493.00p +2.19%GKN (GKN) 223.40p +2.10%British Airways (BAY) 274.00p +2.09%British Sky Broadcasting Group (BSY) 743.00p +1.99%Scottish & Southern Energy (SSE) 1,226.00p +1.91%Royal Bank of Scotland Group (RBS) 40.91p +1.82%Schroders (Non-Voting) (SDRC) 1,461.00p +1.81%Schroders (SDR) 1,858.00p +1.64%FTSE 100 - Fallers3i Group (III) 332.10p -0.92%Smiths Group (SMIN) 1,259.00p -0.87%Inmarsat (ISAT) 680.00p -0.80%Weir Group (WEIR) 1,797.00p -0.77%Amec (AMEC) 1,159.00p -0.77%Reed Elsevier (REL) 528.50p -0.75%African Barrick Gold (ABG) 591.50p -0.59%Capita Group (CPI) 702.50p -0.57%Vodafone Group (VOD) 169.10p -0.53%Shire Plc (SHP) 1,509.00p -0.53%FTSE 250 - RisersCSR (CSR) 342.70p +7.23%Daejan Holdings (DJAN) 2,782.00p +4.19%Sports Direct International (SPD) 158.50p +3.19%Misys (MSY) 327.20p +3.06%Phoenix Group Holdings (DI) (PHNX) 628.50p +3.03%Melrose (MRO) 316.20p +2.86%Mcbride (MCB) 184.50p +2.84%Stagecoach Group (SGC) 215.20p +2.57%Premier Foods (PFD) 18.82p +2.39%Bellway (BWY) 655.50p +2.26%FTSE 250 - FallersMicro Focus International Plc (MCRO) 395.00p -2.73%Supergroup (SGP) 1,229.00p -2.54%Helical Bar (HLCL) 283.10p -2.38%Dixons Retail (DXNS) 22.74p -2.36%Atkins (WS) (ATK) 711.00p -2.27%Gartmore Group Ltd. (GRT) 93.50p -2.20%Dunelm Group (DNLM) 526.00p -2.14%Punch Taverns (PUB) 74.50p -1.91%Go-Ahead Group (GOG) 1,312.00p -1.80%Victrex (VCT) 1,464.00p -1.74%