- Yellen comments rattle markets on tightening fears- FOMC tapers asset purchases by another 10bn dollars/month- Next impresses with full-year results- Changes in Budget continuing to affect stockstechMARK 2,788.04 -1.09%FTSE 100 6,500.19 -1.11%FTSE 250 16,174.99 -1.00%UK stocks dropped sharply on Thursday to their lowest levels in six weeks after newly appointed Federal Reserve Chair Janet Yellen hinted that the US central bank could tighten policy sooner than expected.The FTSE 100 had sunk 1.1% to 6,500 by midday. It has not closed below the 6,500 level since February 5th.Yellen, speaking last night after the Federal Open Market Committee voted to taper its asset purchase programme by another $10bn a month to $55bn, signalled that the first rate hike could come six months after quantitative easing (QE) ends.Stocks on Wall Street quickly dropped in the aftermath, while US bond yields surged and the dollar strengthened against its major counterparts.If the central bank continues to taper at the same rate, QE should come to an end in October or November, which means that interest rates could rise as soon as April or May. Ahead of this week's meeting, analysts had widely expected a rate hike to come towards the end of 2015."Although the Fed's statement implied there would be a 'considerable' gap between the end of QE and the first rate hike, Yellen's definition of considerable as 'around six months' wasn't as long as some had hoped," said Chris Beauchamp, Market Analyst at IG.While Yellen's comments came as a surprise to many, the message delivered about the economy was upbeat, as policymakers lowered their forecasts for unemployment which is set to fall to 6.1-6.3% by the year-end.The Fed also adjusted its forward guidance to put less emphasis on joblessness as a goalpost for when tightening will begin. Instead - similar to Governor Mark Carney's revamped forward guidance at the Bank of England - the Fed will look at a broad range of economic indicators in their decision.Next rises, Budget still affecting stocksNext rose after the High Street retailer reported annual profit that met the top end of its guidance, driven by growth in online sales. The company achieved an 11.8% rise in pre-tax profit to £695m in the year through January 2014, reaching the upper range of the company's forecast of £684m-700m.Insurers Legal & General and Aviva were also making small gains, recovering after a sell-off yesterday on the back of a shake-up to annuities announced by George Osborne in his 2014 Budget. Resolution, however, dropped after saying that the changes have a "negative implication" for new business flows in the individual annuity market.Bookmakers William Hill, Paddy Power and Ladbrokes continued to fall after the Chancellor revealed an increase in gaming machine taxation next year, along with an extension of the horse racing betting levy to include offshore operators. Credit Suisse lowered its forecasts for the three companies this morning, but pointed out that Ladbrokes is the most exposed to the changes. Manufacturing outfit Smiths Group, which yesterday disappointed with its interim results, was extending losses after HSBC lowered its rating on the stock to 'underweight'. Engineering firm Babcock was also suffering from a downgrade by Citigroup to 'neutral'.Heading the other way was electricity provider SSE after receiving a ratings upgrade from Morgan Stanley. Sector peer United Utilities, however, fell after underwhelming with a trading update this morning, which said it expects higher profits and revenues in the year to March 31st.FTSE 100 - RisersSSE (SSE) 1,476.00p +2.64%Next (NXT) 6,695.00p +1.75%Legal & General Group (LGEN) 214.20p +1.42%Standard Life (SL.) 357.30p +0.93%Aviva (AV.) 492.80p +0.49%Amec (AMEC) 1,085.00p +0.37%Prudential (PRU) 1,343.50p +0.30%HSBC Holdings (HSBA) 592.50p +0.12%FTSE 100 - FallersResolution Ltd. (RSL) 318.00p -5.07%Hargreaves Lansdown (HL.) 1,436.00p -4.52%William Hill (WMH) 340.90p -3.02%easyJet (EZJ) 1,585.00p -3.00%Burberry Group (BRBY) 1,388.00p -2.94%ITV (ITV) 196.70p -2.72%Mondi (MNDI) 1,043.00p -2.61%Hammerson (HMSO) 551.00p -2.56%International Consolidated Airlines Group SA (CDI) (IAG) 421.80p -2.47%Randgold Resources Ltd. (RRS) 4,710.00p -2.28%FTSE 250 - RisersSavills (SVS) 634.00p +2.92%Henderson Group (HGG) 256.60p +2.60%Ophir Energy (OPHR) 258.10p +2.54%Diploma (DPLM) 757.00p +2.37%RPS Group (RPS) 329.80p +2.17%Bank of Georgia Holdings (BGEO) 2,262.00p +2.12%St James's Place (STJ) 881.00p +1.79%JD Sports Fashion (JD.) 1,570.00p +1.23%Premier Farnell (PFL) 222.60p +1.18%AL Noor Hospitals Group (ANH) 916.50p +1.05%FTSE 250 - FallersPartnership Assurance Group (PA.) 128.40p -10.21%Intu Properties (INTU) 303.00p -6.25%Ladbrokes (LAD) 132.30p -5.77%Hellermanntyton Group (HTY) 307.40p -4.83%Xaar (XAR) 827.50p -4.22%Home Retail Group (HOME) 215.00p -3.72%Grainger (GRI) 239.60p -3.39%Dairy Crest Group (DCG) 454.30p -3.32%Northgate (NTG) 531.50p -3.10%Barratt Developments (BDEV) 412.20p -2.97%BC