The top share index has staged a strong recovery having plunged below the 5,000 point mark amid continued nervousness over economic growth.The Footsie tumbled below the 4,900 mark in mid-morning trade, with the blue chip index losing over 3% of its value for the second straight session.The sell-off follows the 5-6% decline on the three US benchmarks the night before, on the first day of trading since the ratings agency Standard & Poor's (S&P) cut the US's debt rating from AAA to AA+.Oil prices plummeted well below $100 a barrel on Tuesday, as ongoing anxiety regarding the global economic recovery sparked demand concerns.Investors are now eyeing the US Federal Reserve's policy meeting early this evening London time.Back in London, hotels group InterContinental is posting strong gains. The group's revenue per available room grew by 6.7% from a year earlier in the first half of 2011, driven by strong demand in Greater China and the US, where the Holiday Inn re-launch is delivering sustained outperformance. Royal Bank of Scotland is a heavy faller. Sector peers Barclays and HSBC are also lower. The latter has confirmed that it is in discussions regarding a possible sale of the card and retail services business in the USA.Even Greggs, the bakery chain famous for cheap takeaway snacks, is suffering from the tough consumer environment. Like-for-like sales in the 26 weeks to 2 July were up by just 0.4% from the same period a year ago. The shares are sharply lower.Among smaller companies, shares in Rockhopper Exploration gushed higher after the Falkland Islands oil explorer reported results at the "upper end of expectations" from drilling of its third appraisal well at the Sea Lion feature in the North Falkland Basin. Rockhopper said drilling at the well "confirms significant reservoir development and hydrocarbon charge within Rockhopper's currently interpreted Sea Lion mid-case area." FTSE 100 - RisersWeir Group (WEIR) 1,709.00p +8.16%ARM Holdings (ARM) 499.50p +7.65%InterContinental Hotels Group (IHG) 1,017.00p +5.61%Cairn Energy (CNE) 298.40p +4.92%IMI (IMI) 807.50p +4.73%Antofagasta (ANTO) 1,187.00p +4.49%John Wood Group (WG.) 540.00p +4.35%Petrofac Ltd. (PFC) 1,158.00p +4.32%Johnson Matthey (JMAT) 1,733.00p +3.83%Burberry Group (BRBY) 1,266.00p +3.43%FTSE 100 - FallersRoyal Bank of Scotland Group (RBS) 25.64p -5.94%International Power (IPR) 273.40p -4.51%Fresnillo (FRES) 1,739.00p -3.60%Investec (INVP) 389.10p -3.40%Old Mutual (OML) 104.70p -2.88%Schroders (Non-Voting) (SDRC) 1,154.00p -2.53%National Grid (NG.) 561.00p -2.52%Scottish & Southern Energy (SSE) 1,208.00p -2.34%Legal & General Group (LGEN) 92.10p -2.33%Schroders (SDR) 1,431.00p -2.19%FTSE 250 - RisersHays (HAS) 78.50p +13.11%Thomas Cook Group (TCG) 49.85p +9.54%Renishaw (RSW) 1,360.00p +8.80%Ashtead Group (AHT) 115.50p +7.94%Imagination Technologies Group (IMG) 326.80p +7.15%Travis Perkins (TPK) 778.50p +7.01%Yule Catto & Co (YULC) 173.70p +6.56%Charter International (CHTR) 668.50p +6.20%Centamin Egypt Ltd. (CEY) 96.45p +5.99%Spirit Pub Company (SPRT) 39.16p +5.84%FTSE 250 - FallersCable & Wireless Worldwide (CW.) 32.44p -8.85%Greggs (GRG) 446.40p -7.39%Electra Private Equity (ELTA) 1,371.00p -6.86%Kofax (KFX) 258.20p -6.79%Moneysupermarket.com Group (MONY) 98.10p -5.76%Computacenter (CCC) 368.00p -5.67%Impax Environmental Markets (IEM) 94.80p -5.48%Daejan Holdings (DJAN) 2,350.00p -5.17%JPMorgan Asian Inv Trust (JAI) 196.10p -4.99%JPMorgan Russian Securities (JRS) 518.00p -4.95%