London close: Stocks pare gains after US data

Disappointing economic from the States saw the FTSE 100 halve its earlier gains by the close on Wednesday as markets waited in anticipation of a policy decision from the Federal Reserve later this evening.The US central bank is widely expected to leave its current stimulus measures unchanged following its two-day meeting given that employment and economic growth figures have disappointed over recent weeks.Financial Trader David White from Spreadex said: "Very few participants believe this is a healthy market. But so long as there's easing and printing, few seem to care. Numbers that don't frighten off quantitative easing but that do not cause concern are what the bulls are looking for."Dampening sentiment this afternoon was the ADP employment report, seen as a rough guide to the official US jobs report on Friday, which saw a 119,000 rise in private payrolls in April, down from the 131,000 gain the month before and well below the 150,000 consensus forecast.Manufacturing purchasing managers' indices from both the US and China also underwhelmed today, pointing to a slowdown in industrial output from the world's two largest economies. Volumes were said to have been light today given that most other stock markets across Europe remained closed for the May Day public holiday.While today's focus was on the Fed, the European Central Bank (ECB) will likely dominate the headlines tomorrow as it convenes to discuss a possible interest-rate cut given that recent Eurozone economic data continued to paint a gloomy picture for the single-currency region. What's more, yesterday's inflation figures showed that consumer-price rises slowed down sharply in April, adding to speculation that the ECB will cut its key 'refi' rate from the already-record-low level of 0.75%. FTSE 100: BT Group shares were leading the risers on Wednesday after the company this week signed a 10-year deal with o2 to create a new 4G network worth in the region of £500m.Speciality chemicals group Johnson Matthey has made strong gains after a positive update from Credit Suisse said that weaker platinum prices have not proven to be a drag on precious metal products and said it is optimistic about its fourth-quarter performance. Industrial investment firm Melrose was also in demand after it sold its Truth Hardware division to AIM-listed building product group Tyman for $200m. Mining giant ENRC was firmly lower on reports that the UK Listings Authority has launched an investigation into potential breaches of takeover rules. Headlines this morning were also focusing on issues with the company's flotation in 2007. Admiral, Croda, ITV and Reed Elsevier were also among the worst performers of the day after going ex-dividend, meaning that new investors have now missed the opportunity to tap in to each companies' latest payout. Reed Elsevier was also being weighed down by a ratings cut by UBS from 'buy' to 'neutral'.FTSE 250: NMC Health hit by downgradeNMC Health was a heavy faller today, extending losses after yesterday's first-quarter results. Numis Securities downgraded its rating for the stock yesterday to 'hold'.Aviation services group BBA Aviation was making strong gains after JP Morgan Cazenove reiterated its 'overweight' rating on the stock. Meanwhile, transport firm National Express was higher after Liberum Capital upped the shares to 'buy'.Home Retail Group fell after seeing a drop in annual profits as a decline in sales at its Homebase subsidiary offset strong results at Argos.FTSE 100 - RisersBT Group (BT.A) 285.70p +3.44%ARM Holdings (ARM) 1,026.00p +3.01%Johnson Matthey (JMAT) 2,485.00p +2.52%Melrose Industries (MRO) 250.00p +2.42%Kingfisher (KGF) 320.30p +2.30%Experian (EXPN) 1,153.00p +1.86%Aviva (AV.) 310.10p +1.64%Standard Chartered (STAN) 1,642.00p +1.55%Serco Group (SRP) 628.00p +1.54%TUI Travel (TT.) 319.00p +1.50%FTSE 100 - FallersEurasian Natural Resources Corp. (ENRC) 262.80p -4.23%Admiral Group (ADM) 1,241.00p -3.12%Reed Elsevier (REL) 729.00p -3.06%Evraz (EVR) 150.30p -3.03%Polymetal International (POLY) 680.00p -2.23%Weir Group (WEIR) 2,156.00p -2.18%G4S (GFS) 307.00p -1.85%Burberry Group (BRBY) 1,314.00p -1.65%CRH (CRH) 1,365.00p -1.23%Rexam (REX) 510.50p -1.16%FTSE 250 - RisersBBA Aviation (BBA) 265.10p +5.66%Dixons Retail (DXNS) 36.50p +3.99%Man Group (EMG) 106.00p +3.72%Diploma (DPLM) 591.50p +3.68%Inmarsat (ISAT) 749.00p +3.67%National Express Group (NEX) 198.40p +3.60%Grainger (GRI) 140.90p +3.60%Dignity (DTY) 1,424.00p +3.41%Wetherspoon (J.D.) (JDW) 607.50p +3.40%Homeserve (HSV) 216.10p +3.20%FTSE 250 - FallersNMC Health (NMC) 276.70p -10.74%African Barrick Gold (ABG) 160.60p -8.23%Home Retail Group (HOME) 144.90p -7.00%Heritage Oil (HOIL) 151.80p -5.12%Kazakhmys (KAZ) 334.30p -3.47%Ferrexpo (FXPO) 172.70p -2.87%Elementis (ELM) 256.40p -2.69%New World Resources A Shares (NWR) 151.00p -2.58%Lonmin (LMI) 263.60p -2.01%Millennium & Copthorne Hotels (MLC) 555.00p -1.86%BC