London open: Fed comments provide support ahead of BoE, ECB

The FTSE 100 held on to recent gains on Thursday morning ahead of central-bank policy decisions in the UK and Europe, as comments from the Federal Reserve provided some support.According to the Fed's Beige Book released last night, the US economy expanded at a "modest to moderate pace" at the start of 2013 due to strong car sales, hiring gains and a recovery in the housing sector.The UK benchmark index surged to levels not seen since late 2007 earlier this week a better-than-expected reading of US services activity and a pledge by China to hit its growth targets this year boosted markets.It appears that markets were pausing for breath today ahead of policy decisions from the Bank of England and European Central Bank expected after midday. Speculation has increased over the last month about changes to policy from both sides so investors are likely to sit on their hands and refrain from taking risk until someone makes a move.Overnight, the Bank of Japan voted to keep interest rates and its asset purchase programme unchanged, a decision that was widely expected given the Bank's recent aggressive easing.FTSE 100: Aviva plummets after 'rebasing' diviInsurance giant Aviva was forced to slash to dividend after swinging into the red in 2012, after taking a 3.3bn-pound write-down on a disposal in the US. Aviva also said that its overall situation does not warrant bonuses for executive directors for 2012 or pay rises for 2013. Shares dropped sharply early on.Heading the other way was temporary power and temperature control provider Aggreko after posting a strong performance with trading profit up 13% last year.Insurance provider Standard Life gained after unveiling a windfall dividend worth £302m after delivering substantial growth in profits in 2012 underpinned by strong performance in the UK.British asset management firm Schroders was higher after saying that assets under management (AuM) reached record levels in spite of choppy markets and falling profits.Pharma giant GlaxoSmithKline rose after announcing positive data from a drug study through ViiV Healthcare, a global specialist HIV company set up by GSK in 2009.FTSE 250: National Express dropsTransport group National Express was a heavy faller after reports yesterday said that US investor Elliot Advisors plans to sell over 50m worth of shares, equal to a 9.9% stake.Engineering firm Spirax-Sarco was in demand after proposing a special dividend of 100p per share in addition to an 8.0% rise in the full-year payout, after a 2.0% rise in revenue in 2012.FTSE 100 - RisersAggreko (AGK) 1,932.00p +9.90%IMI (IMI) 1,328.00p +5.23%Admiral Group (ADM) 1,362.00p +2.10%Standard Life (SL.) 380.30p +1.63%Unilever (ULVR) 2,721.00p +1.45%Barclays (BARC) 306.50p +1.44%Reckitt Benckiser Group (RB.) 4,568.00p +1.15%Antofagasta (ANTO) 1,075.00p +1.03%Kazakhmys (KAZ) 560.50p +0.99%Schroders (SDR) 2,056.00p +0.98%FTSE 100 - FallersAviva (AV.) 310.80p -13.62%Melrose Industries (MRO) 260.10p -2.62%Polymetal International (POLY) 958.00p -1.79%British Sky Broadcasting Group (BSY) 874.00p -1.63%Morrison (Wm) Supermarkets (MRW) 259.20p -1.52%Lloyds Banking Group (LLOY) 50.30p -1.41%Serco Group (SRP) 621.50p -0.88%Vodafone Group (VOD) 178.60p -0.78%Legal & General Group (LGEN) 164.90p -0.66%Old Mutual (OML) 208.80p -0.62%FTSE 250 - RisersRegus (RGU) 149.50p +4.18%Spirax-Sarco Engineering (SPX) 2,578.00p +3.00%RIT Capital Partners (RCP) 1,202.00p +2.56%SEGRO (SGRO) 264.60p +2.44%Cobham (COB) 234.20p +2.18%Betfair Group (BET) 702.00p +2.03%Jupiter Fund Management (JUP) 344.60p +1.83%Ashtead Group (AHT) 585.00p +1.74%Rotork (ROR) 2,951.00p +1.58%SIG (SHI) 142.50p +1.50%FTSE 250 - FallersNational Express Group (NEX) 206.90p -10.04%Petropavlovsk (POG) 257.10p -6.34%Hunting (HTG) 889.50p -4.51%Inmarsat (ISAT) 636.50p -4.36%IP Group (IPO) 135.00p -3.23%Balfour Beatty (BBY) 279.30p -2.68%Heritage Oil (HOIL) 192.50p -2.19%International Personal Finance (IPF) 463.90p -2.01%African Barrick Gold (ABG) 241.10p -1.87%Rank Group (RNK) 163.00p -1.69%BC