Mining stocks were once again bearing the brunt of a fall in risk appetite on Wednesday as concerns over demand for commodities were sparked by some disappointing economic data from China. Anglo American, Glencore Xstrata, BHP Billiton, Vedanta and Antofagasta were among the worst performers. Leading the upside today was engineer and automotive components maker GKN after data out last night showed that US vehicle sales came in much better than expectations in June. Tullow Oil wasn't far behind after a strong first-half operational update. The company said that revenue totalled $1.3bn, slightly ahead of the $1.2bn reported the year before, as the company upgraded its resource estimates for certain projects in Kenya. Sector peer Shell however fell despite revealing upbeat drilling results from an exploratory well in the Gulf of Mexico. The well, located 75 miles offshore in the De Soto Cayon Block 393, encountered more than 500ft of net oil pay, but that wasn't enough to boost the share price today.Burberry was trading firmly in the red after going ex-dividend, along with heavyweights British Land and Babcock.Banking group Barclays was also lower after S&P cut its credit rating by one notch, saying that its debt holders "face heightened credit risk owing to the industry's tighter regulation, fragile global markets, stagnant European economies and rising litigation risk stemming from the financial crisis".UBS issued an upbeat research note on chip designer ARM Holdings this morning. In their opinion nothing has fundamentally changed in the company's investment case. By their estimates, for example, the stock price already reflects several sources of concern amongst investors, such as Intel gaining market share in the mobile space. Conversely, in their opinion the shares are not yet discounting several 'positives' remaining for ARM. The company's shares are in the process of filling-in a small bearish gap which had been previously left behind and are now facing a first area of technical resistance towards 833p, its 200-day moving average.FTSE 100 - RisersGKN (GKN) 309.60p +2.52%Tullow Oil (TLW) 1,054.00p +2.03%ARM Holdings (ARM) 818.00p +1.30%Eurasian Natural Resources Corp. (ENRC) 208.90p +0.97%TUI Travel (TT.) 359.00p +0.81%G4S (GFS) 226.30p +0.76%ITV (ITV) 145.50p +0.76%London Stock Exchange Group (LSE) 1,406.00p +0.72%Next (NXT) 4,666.00p +0.71%Severn Trent (SVT) 1,696.00p +0.65%FTSE 100 - FallersAnglo American (AAL) 1,213.50p -5.20%CRH (CRH) 1,291.00p -4.65%Weir Group (WEIR) 2,078.00p -3.75%Glencore Xstrata (GLEN) 266.95p -3.28%Burberry Group (BRBY) 1,359.00p -3.27%BHP Billiton (BLT) 1,655.50p -3.24%Vedanta Resources (VED) 1,007.00p -3.08%Standard Chartered (STAN) 1,419.00p -3.04%Antofagasta (ANTO) 803.50p -2.67%Old Mutual (OML) 179.40p -2.66%