London open: Markets flat as investors await FOMC, economic data

Markets in the UK opened broadly flat on Wednesday morning as investors adopted a wait-and-see approach ahead of a policy announcement from the Federal Reserve.All eyes will be on the Federal Open Market Committee as its two-day meeting comes to a close this evening. While few actually think that the Fed will begin to scale back its quantitative easing programme this month - analysts are widely expects the 'tapering' to start in September - traders will be on edge of their seats, looking out for hints of a timeframe for the withdrawal of stimulus.Market Analyst Craig Erlam from Alpari said it's always difficult to try and guess what the Fed is going to do: "Even when correct, markets can be so volatile around the decision and the release of the statement, that most forms of technical analysis go out of the window and it can be very difficult to profit from it."That's why we always tend to see similar scenarios to what we have this morning, with markets opening largely flat."Also in focus today will be a raft of economic data (not to mention corporate earnings), including German unemployment figures, the Eurozone consumer price index, US second-quarter growth estimates and the Chicago purchasing managers' index.Meanwhile, tomorrow will see the release of the Bank of England and European Central Bank policy decisions. FTSE 100: Centrica, Tullow and Antofagasta impress with H1 reportsCentrica, the energy company which owns British Gas, was a high riser this morning after reporting a "robust" financial performance in the six months to June 30th, with revenue up 14% at £13.7bn after customers used more gas to stay warm during an unusually cold winter.Oil explorer Tullow gained after reporting a 15% jump in first-half revenue to $1.3bn on the back of an increase in production. Sector peer BP meanwhile was rebounding after investors yesterday gave a cool reaction to its second-quarter results.South America-focused mining group Antofagasta gained despite seeing copper output fall from the first to the second quarter, as it said it was still on track to hit its full-year target of 700,000 tonnes, more or less in line with last year.Diageo, the beverages company behind the Guinness, Baileys and Smirnoff brands, achieved a solid 5.0% growth in full-year net sales but said trading still remained "challenging" in Western Europe, causing shares to fall early on.Banking group Barclays was extending losses made the day before after it revealed plans for a £5.8bn rights issue and reported a drop in profits in the first half. Sector peers Lloyds and RBS were also under pressure.Utilities firm SSE however was the standout faller after going ex-dividend.FTSE 100 - RisersGKN (GKN) 356.80p +2.38%Centrica (CNA) 391.70p +1.53%Legal & General Group (LGEN) 193.50p +1.10%Croda International (CRDA) 2,522.00p +1.08%London Stock Exchange Group (LSE) 1,568.00p +0.84%Antofagasta (ANTO) 882.00p +0.80%Imperial Tobacco Group (IMT) 2,184.00p +0.78%Marks & Spencer Group (MKS) 480.00p +0.76%BP (BP.) 454.80p +0.74%Tullow Oil (TLW) 1,034.00p +0.68%FTSE 100 - FallersSSE (SSE) 1,568.00p -4.27%Barclays (BARC) 286.20p -1.75%Diageo (DGE) 1,966.50p -1.16%Weir Group (WEIR) 2,140.00p -1.11%Eurasian Natural Resources Corp. (ENRC) 216.40p -1.10%Wolseley (WOS) 3,121.00p -1.01%Travis Perkins (TPK) 1,684.00p -0.94%Aviva (AV.) 370.70p -0.91%Vedanta Resources (VED) 1,166.00p -0.85%Lloyds Banking Group (LLOY) 67.14p -0.75%FTSE 250 - RisersSt James's Place (STJ) 618.50p +4.21%F&C Asset Management (FCAM) 98.00p +3.70%Brewin Dolphin Holdings (BRW) 252.90p +3.52%Rightmove (RMV) 2,386.00p +3.29%Bumi (BUMI) 220.00p +3.19%Rank Group (RNK) 156.30p +2.83%Invensys (ISYS) 500.50p +1.98%Bwin.party Digital Entertainment (BPTY) 138.40p +1.84%Renishaw (RSW) 1,559.00p +1.83%Essentra (ESNT) 762.50p +1.80%FTSE 250 - FallersMoneysupermarket.com Group (MONY) 181.00p -14.70%International Personal Finance (IPF) 629.50p -2.70%Investec (INVP) 435.20p -2.51%Daejan Holdings (DJAN) 3,971.00p -1.90%African Barrick Gold (ABG) 109.50p -1.71%Fenner (FENR) 342.00p -1.47%BH Macro Ltd. GBP Shares (BHMG) 2,191.00p -1.26%Ferrexpo (FXPO) 168.30p -1.23%Interserve (IRV) 509.00p -1.17%JPMorgan Indian Inv Trust (JII) 340.00p -1.16%BC