Royal Bank of Scotland (RBS) plunged lower after the announcment of Moody's decision to downgrade the bank's credit rating by two notches, which poured more fuel on rumours that the firm could need an extra injection of capital from the government.RBS issued a statement on Friday morning highlighting its disappointment with the news, which also saw the ratings agency lower its rating on 11 other financial institutions. Lloyds was also affected by the en-masse downgrade, although shares fell by less as its rating was cut by just one notch.Mining giant Xstrata was heading in the opposite direction after announcing that it has - through its Xstrata Coal subsidiary - agreed to buy the Lossan metallurgical coal deposit from Cline Mining Corporation for C$40m (£24.9m)."Lossan is located in the Peace River Coalfield of north eastern British Columbia, Canada, and is surrounded by a group of licences recently acquired by Xstrata Coal through the acquisition of First Coal Corporation in early August 2011," the group said. Heating and plumbing giant Wolseley was the high riser though, gaining over 5% after revealing huge upwards swing in the P&L account earlier in the week. FTSE 100 - RisersWolseley (WOS) 1,739.00p +5.14%Xstrata (XTA) 923.90p +4.31%Weir Group (WEIR) 1,592.00p +3.98%ITV (ITV) 62.85p +3.80%Vedanta Resources (VED) 1,154.00p +3.68%Kingfisher (KGF) 256.00p +3.43%Burberry Group (BRBY) 1,246.00p +3.32%InterContinental Hotels Group (IHG) 1,061.00p +3.21%Man Group (EMG) 167.60p +3.08%Petrofac Ltd. (PFC) 1,255.00p +2.78%FTSE 100 - FallersRoyal Bank of Scotland Group (RBS) 23.63p -3.00%Admiral Group (ADM) 1,229.00p -2.38%SABMiller (SAB) 2,195.50p -2.31%Unilever (ULVR) 2,007.00p -2.10%British Sky Broadcasting Group (BSY) 675.00p -2.10%Whitbread (WTB) 1,602.00p -2.02%Lloyds Banking Group (LLOY) 35.32p -1.52%Legal & General Group (LGEN) 101.40p -1.46%RSA Insurance Group (RSA) 113.10p -1.39%Essar Energy (ESSR) 265.50p -1.34%NR