Heavyweight mining stocks were in the red today as risk appetite declined ahead of the US. ENRC, EVRAZ, Rio Tinto, Anglo American, Fresnillo, Antofagasta and Glencore were among the worst performers. ENRC was the biggest faller after Business Secretary Vince Cable was called upon to launch an official investigation into the miner and sector peer Bumi. ccording to a letter from PIRC, the independent advisory consultancy to institutional investors, the government should use its powers under the Companies Act to launch an investigation into ENRC and Bumi on the basis they "fall short of the standard expected of UK listed companies". Also in the red was Croda International after Numis reduced its target price from 2,565p to 2,537p, keeping a hold recommendation. Advertising and media firm WPP was out of favour after its first-quarter trading update. While the company said that its performance in the UK and emerging markets helped offset weaker growth in its mature markets in the US and Western Europe, it warned that clients were still reluctant to take further risks in the face of challenging economic conditions. Meanwhile, business process management provider Capita rose into the top spot after saying that it will form a joint venture company with the UK Cabinet Office to commercialise the government's portfolio of best management practice training tools. Prudential also made decent gains after announcing the appointment of Jackie Hunt as Chief Executive Officer for the Prudential UK and Europe division. Hunt, who will join the group from Standard Life where she is currently Chief Financial Officer, and will succeed Rob Devey, who is leaving the group at the end of October. The news pushed Standard Life shares firmly into decline. FTSE 100 - RisersCapita (CPI) 881.50p +2.20%Kingfisher (KGF) 313.00p +1.13%Prudential (PRU) 1,101.00p +0.92%Whitbread (WTB) 2,559.00p +0.87%Bunzl (BNZL) 1,261.00p +0.80%Schroders (SDR) 2,271.00p +0.62%HSBC Holdings (HSBA) 694.70p +0.61%ITV (ITV) 128.10p +0.55%National Grid (NG.) 804.00p +0.50%Tesco (TSCO) 366.75p +0.48%FTSE 100 - FallersEurasian Natural Resources Corp. (ENRC) 272.40p -5.74%Polymetal International (POLY) 758.50p -3.62%Evraz (EVR) 161.00p -3.36%Glencore International (GLEN) 320.15p -3.20%Xstrata (XTA) 974.00p -3.08%Antofagasta (ANTO) 925.00p -2.99%Croda International (CRDA) 2,514.00p -2.86%Anglo American (AAL) 1,604.50p -2.70%GKN (GKN) 266.90p -2.38%Rio Tinto (RIO) 2,969.50p -2.38%NR