Mining stocks were among the best performers on Monday afternoon after UBS said that 2013 could provide meaningful upside to some commodity prices."In our opinion, the macro backdrop for commodities is improving, with the new Chinese/ US governments promising pro-growth policy," the broker said.Rio Tinto was on the up after UBS labelled it as its preferred stock . Sector peers Polymetal, Kazakhmys, Antofagasta and BHP Billiton were also rising.However, Anglo American was bucking the trend after the broker downgraded its rating for the firm from 'buy' to 'neutral'. The company was also under pressure following a downbeat note out of analysts at JP Morgan who reiterated their underweight stance. It would seem that some investors are worried that the company will not move quickly enough - if at all - to spin-off its Amplats division. Oil giant BP was lower after Credit Suisse lowered its rating from 'outperform' to 'neutral', citing the stock's valuation and "lack of near-term momentum". Sector peer Tullow was also down. In contrast, distribution and outsourcing group Bunzl was lifted by Citigroup which raised its rating to 'buy'.Security firm G4S edged lower after announcing that it is to acquire an 87% stake in South African retail cash solutions technology provider Deposita for £8.2m. FTSE 100 - RisersPolymetal International (POLY) 1,179.00p +2.61%Kazakhmys (KAZ) 759.50p +2.08%Croda International (CRDA) 2,375.00p +1.32%Rio Tinto (RIO) 3,379.50p +1.23%Experian (EXPN) 1,011.00p +1.20%Antofagasta (ANTO) 1,357.00p +0.97%Evraz (EVR) 261.40p +0.89%International Consolidated Airlines Group SA (CDI) (IAG) 173.20p +0.87%SSE (SSE) 1,443.00p +0.70%BHP Billiton (BLT) 2,086.50p +0.70%FTSE 100 - FallersPrudential (PRU) 882.00p -1.84%Anglo American (AAL) 1,825.50p -1.70%Weir Group (WEIR) 1,808.00p -1.53%Admiral Group (ADM) 1,136.00p -1.47%National Grid (NG.) 707.00p -1.46%Tullow Oil (TLW) 1,200.00p -1.32%AstraZeneca (AZN) 2,919.50p -1.32%Legal & General Group (LGEN) 144.90p -1.16%Imperial Tobacco Group (IMT) 2,425.00p -1.10%Aggreko (AGK) 2,125.00p -0.89%BC