London's blue chips have opened lower as investors consider a slew of big corporate announcements and rumours surrounding the British banking sector.The European Commission is expected to approve plans to break up and sell Northern Rock, according to press reports.The Independent is quoting a British Government sources as saying that ministers were 'determined' to see more competition in the market. Part-nationalised lenders Lloyds Banking and Royal Bank of Scotland will also be broken up over the next three to five years, the paper adds.BG Group has reported a drop in third quarter pre-tax profit to £838m from £1.53bn a year ago, with nine-month profit down to £3bn from £4.20bn. The oil giant said net income fell to £484m in the three months to September, down from £857m the same time last year.Prudential lifted group-wide retail sales by 10% to £699m in the third quarter thanks largely to a surge in business in the US. Retail sales leapt 66% in the US to a record £249m, easily offsetting a 22% decline to £157m in the UK. Sales in Asia rose 4% to £293m.Tobacco firm British American Tobacco said it performed well in the nine months to the end of September, although total volume growth has slowed. Revenue for the nine months grew strongly in constant currency terms, it added, driven by the continued good pricing momentum and volume growth from acquisitions.Gas supplier Centrica has received planning permission for the construction of a wind farm project off the coast of Lincolnshire. US investment management company TCW has agreed to pay £84m for a 50% equity stake in Centrica's Lynn, Inner Dowsing and Glens of Foudland wind farms, the company added.Rio Tinto has paid $388m for another 9.8% of Canada's Ivanhoe Mines after completing the second tranche of its private placement investment, taking its total interest to 19.7%.Drugs giant AstraZeneca has yanked the US and European regulatory submissions for its lung cancer treatment Zactima. The applications were submitted in June but after further analysis of test results no overall survival advantage was discerned when chemotherapy treatment was augmented by a dose of Zactima.Dana Petroleum has discovered oil at the Jetta prospect offshore Norway, though tests will have to determine if the discovery is commercial.Floor coverings retailer Carpetright expects half-year results to be ahead of expectations after sales growth put on a spurt in the last six weeks. The UK and the Republic of Ireland put in a strong performance but the economic downturn contributed to a slump in sales in the Netherlands and Belgium.Electronic components maker Laird has confirmed recent press speculation that it is considering an equity issue.FTSE 100 - RisersG4S (GFS) 248.80p +0.57%Alliance Trust (ATST) 318.00p +0.51%Bunzl (BNZL) 664.50p +0.45%BT Group (BT.A) 134.00p +0.37%United Utilities Group (UU.) 447.00p +0.29%BAE Systems (BA.) 321.90p +0.28%Cadbury (CBRY) 776.50p +0.19%FTSE 100 - FallersMan Group (EMG) 317.20p -4.26%Royal Bank of Scotland Group (RBS) 39.48p -3.23%Wolseley (WOS) 1,329.00p -2.71%BG Group (BG.) 1,103.00p -2.60%Autonomy Corporation (AU.) 1,365.00p -2.15%Legal & General Group (LGEN) 80.80p -2.12%BHP Billiton (BLT) 1,747.00p -1.96%