The top share index closed in the red despite a bright start to the day, continuing the volatile performance seen last week. Energy supplier Centrica is a struggler after saying it expects profits growth in 2011 to be more subdued than previously anticipated due to the new tax regime on UK oil production. The increase in the Supplementary Charge (SCT) rate, from 20% to 32%, on UK production announced in March in the government's budget offsets the benefit of higher commodity prices on its production business, the group claimed.Inmarsat is a high flyer after the satellite communications giant Inmarsat said total quarterly revenue rose 15% boosted by payments from its agreement with US telecoms group LightSquared.Platinum miner Lonmin is wanted after it released first half results and second quarter production figures. The South African company has been ramping up production as prices for platinum stay high. It mined 2.9m tonnes in the quarter to 31 March, up 10% from the same period last year. In the six months to 31 March, pre-tax profits climbed to $159m (£97.2m) from $77m on revenues that soared to $938m from $661m. Casino and bingo hall operator Rank moves ahead after it advised its shareholders against accepting a 150p a share offer for the company, saying it "significantly undervalues Rank and its prospects."Travel company Thomas Cook said it remains well positioned to make progress this year despite losses arising from unrest in the Middle East and North Africa. Political upheaval in the region and the shift of Easter into the second half resulted in an increased seasonal operating loss of £166m, up £36m. "We estimate that the MENA situation has cost the group £22m in the first half, whilst the shift of Easter had an impact of around £15m," Thomas Cook said.Builders' merchant Travis Perkins said revenue rose 5.9% for the four months ended April 2011 as it gained a bigger market share. The owner of DIY and home improvement products supplier Wickes said it was pleased with the overall progress of the group despite markets that continue to offer little or no growth. Data centre operator Telecity has confirmed a positive outlook for the year ahead, saying strong European demand should lead to "substantial growth" in 2011. The firm said it had secured an additional £100m of debt financing to help push expansion in Europe, bringing its total credit facility to £300m. Specialist insurer Hiscox said on Monday that sales fell 8% in the first three months of 2011, compared with a year earlier. Gross written premiums were £453.5m in the three months until the end of March amid a "tough" market, the firm said. "We continue to underwrite for profit over volume in these tough market conditions," said chief executive Bronek Masojada.Outsourcing giant Serco is drawing comfort from its £29bn pipeline of identified opportunities despite some short-term headwinds in the UK, and is on course to hit its 2011 targets.Anglo-Dutch household goods giant Unilever has received regulatory clearance to acquire US personal care and household brands firm, Alberto Culver, after agreeing to divest the Alberto VO5 and Rave brands in the US.Flooding and cyclones in Australia hurt RPS's trading in the first quarter of 2011, but the environmental services group remains upbeat. Profits in the first half are likely to be similar to those in 2010, as a result of the Australian disruption RPS said, adding that growth in the second half should allow market expectations for 2011 to be achieved.FTSE 100 - RisersInmarsat (ISAT) 619.00p +4.38%Autonomy Corporation (AU.) 1,675.00p +3.91%IMI (IMI) 1,081.00p +2.17%Sage Group (SGE) 285.80p +1.64%Vodafone Group (VOD) 170.10p +1.49%Intertek Group (ITRK) 2,089.00p +1.21%BT Group (BT.A) 197.00p +1.13%Burberry Group (BRBY) 1,302.00p +0.93%ICAP (IAP) 508.00p +0.89%Lonmin (LMI) 1,562.00p +0.84%FTSE 100 - FallersCentrica (CNA) 303.50p -3.80%Royal Bank of Scotland Group (RBS) 41.70p -2.43%International Consolidated Airlines Group SA (IAG) 248.40p -2.24%ITV (ITV) 74.00p -2.12%United Utilities Group (UU.) 613.00p -2.08%Standard Chartered (STAN) 1,572.00p -1.96%Capital Shopping Centres Group (CSCG) 397.20p -1.88%Carnival (CCL) 2,556.00p -1.69%Schroders (Non-Voting) (SDRC) 1,355.00p -1.67%Eurasian Natural Resources Corp. (ENRC) 868.00p -1.64%FTSE 250 - RisersMisys (MSY) 343.50p +8.36%Aveva Group (AVV) 1,632.00p +4.41%CSR (CSR) 368.00p +3.66%Ferrexpo (FXPO) 468.00p +3.33%Micro Focus International Plc (MCRO) 385.00p +3.27%Kenmare Resources (KMR) 43.50p +3.08%WH Smith (SMWH) 493.40p +2.86%Senior (SNR) 153.70p +2.47%Kofax (KFX) 458.00p +2.46%Dixons Retail (DXNS) 15.64p +2.16%FTSE 250 - FallersTalvivaara Mining Company (TALV) 482.50p -3.44%Lamprell (LAM) 349.10p -3.43%Telecity Group (TCY) 513.50p -3.30%Centamin Egypt Ltd. (CEY) 122.70p -3.16%Thomas Cook Group (TCG) 165.70p -2.87%Bwin.party Digital Entertainment (BPTY) 146.00p -2.67%easyJet (EZJ) 346.80p -2.34%JPMorgan Indian Inv Trust (JII) 422.20p -2.31%Yule Catto & Co (YULC) 208.30p -2.21%COLT Group SA (COLT) 142.80p -2.19%