After an initial stint in positive territory, UK stock markets swung sharply into the red by Friday lunchtime as concerns about budget cuts in the US take their toll on risk appetite.Sequestration is continuing to dominate headlines this morning as the deadline for across-the-board automatic budget cuts worth $85bn passes today. The International Monetary Fund has warned that it would be forced to trim is economic growth estimates if the cuts went ahead.While the cuts would be gradual, it is thought that they will shave 0.5 percentage points off US gross domestic product growth this year.Market Analyst Craig Erlam from Alpari said: "I don't think the sequestration will have a longer term impact on the markets though, compared to the potential impact of the fiscal cliff at the end of last year, this is only small. "I think what we're seeing today is simply a case of people firstly demonstrating their lack of belief that the US government can get the job done, but also with it being the end of the week, people are closing their positions and locking in profits from the past couple of days."Worse-than-expected manufacturing figures from China and the UK were also weighing on sentiment today, meaning that the mining sector was firmly out of favour.The official Chinese manufacturing purchasing managers' index (PMI) fell from 50.4 to 50.1 in February. While this marked the fifth straight month of expansion (shown by figures above the mid-point of 50), analysts were expecting a slight rise to 50.5.HSBC's own PMI survey for Chinese manufacturing also fell from 52.3 to 50.4 in February, missing the 50.6 estimate.Meanwhile, the Markit/CIPS manufacturing PMI in the UK dropped from a revised 50.5 to 47.9 this month, missing the 51 estimate.FTSE 100: Miners tank after Chinese data; Lloyds disappointsMining stocks were providing a drag on the Footsie today in the wake of the disappointing economic figures from China. Kazakhmys, EVRAZ, Xstrata, Glencore, ENRC and Polymetal were registering steep losses.Kazakhmys, which yesterday announced that it would be slashing its dividend to reflect falling profits in 2012, was a heavy faller after Bank of America, JPMorgan and Exane BNP Paribas all cut their target prices for the stock.Meanwhile, Glencore and Xstrata were also hit after saying that they would likely push back their merger deadline as they continue to await regulatory approval in China.UK banking group Lloyds sank this morning after reporting that while underlying profits soared in 2012, it was forced to take further provisions for Payment Protection Insurance (PPI) redress in the fourth quarter.Advertising giant WPP topped market expectations with its results for 2012 but labelled its performance as "ugly" due to the varying levels of growth throughout the year. Shares edged slightly higher.Insurance group Old Mutual was in demand after posting an 18% increase in annual profits in 2012, driven by a strong performance in Africa.Meanwhile, property developer Hammerson gained after hailing 2012 as a "transformational year" which saw 2.1% growth in like-for-like net rental income.After reporting record 2012 sales yesterday, outsourcing group Capita was a high riser after saying that has acquired debt recovery specialists iQor Holdings UK and subsidiaries (iQor UK) for an enterprise value of £42m.FTSE 250: William Hill surges after results, acquisition, rights issueHigh Street betting shop William Hill jumped after announcing that it is buying out its partner Playtech in the William Hill Online venture for £424m, funded by a fully underwritten rights issue of £375m. The company also met profit forecasts with 22% bottom-line growth in 2012.Fund manager Man Group was a heavy faller after UBS downgraded the stock from 'buy' to 'neutral', saying it is "waiting for more visibility" on a number of key stock drivers.FTSE 100 - RisersCapita (CPI) 851.00p +3.34%Hammerson (HMSO) 504.50p +2.04%Experian (EXPN) 1,111.00p +1.55%British American Tobacco (BATS) 3,487.50p +1.54%Compass Group (CPG) 812.00p +1.44%Tate & Lyle (TATE) 823.50p +1.35%Babcock International Group (BAB) 1,087.00p +1.30%Reckitt Benckiser Group (RB.) 4,485.00p +1.26%InterContinental Hotels Group (IHG) 1,937.00p +1.20%Land Securities Group (LAND) 838.50p +1.08%FTSE 100 - FallersLloyds Banking Group (LLOY) 50.90p -6.55%Kazakhmys (KAZ) 582.00p -5.98%Royal Bank of Scotland Group (RBS) 308.10p -4.88%Xstrata (XTA) 1,112.50p -4.30%Evraz (EVR) 261.80p -4.07%Glencore International (GLEN) 371.75p -4.06%Eurasian Natural Resources Corp. (ENRC) 326.00p -3.66%Polymetal International (POLY) 966.00p -3.30%Rio Tinto (RIO) 3,426.00p -3.25%Barclays (BARC) 298.05p -2.92%FTSE 250 - RisersWilliam Hill (WMH) 435.00p +7.49%Hikma Pharmaceuticals (HIK) 913.50p +5.49%IP Group (IPO) 136.00p +2.33%Synthomer (SYNT) 211.50p +2.27%St James's Place (STJ) 497.70p +2.20%Berendsen (BRSN) 696.50p +2.05%Atkins (WS) (ATK) 886.00p +1.96%Rightmove (RMV) 1,756.00p +1.92%Bwin.party Digital Entertainment (BPTY) 150.90p +1.89%Enterprise Inns (ETI) 107.80p +1.79%FTSE 250 - FallersFerrexpo (FXPO) 216.10p -5.09%Petropavlovsk (POG) 287.10p -4.87%Man Group (EMG) 96.10p -4.19%Bumi (BUMI) 323.80p -3.66%UBM (UBM) 751.00p -2.97%Hays (HAS) 95.30p -2.90%New World Resources A Shares (NWR) 256.80p -2.84%African Barrick Gold (ABG) 255.40p -2.82%Jupiter Fund Management (JUP) 327.00p -2.71%Supergroup (SGP) 617.50p -2.53%BC