UK stocks finished a choppy session marginally in positive territory on Wednesday as investor risk appetite was curbed by pre-election uncertainty and cautious comments from Federal Reserve chair Janet Yellen.The FTSE 100 closed up 6.16 points (+0.09%) at 6,933.74, rebounding slightly after settling at a one-month low the previous session.However, the index ended well below the intraday high of 6,974.82 reached early on. Not even a forecast-beating survey on the UK services sector could lift the mood as City traders attempted to predict the outcome of Thursday's electoral vote."With fewer than 24 hours before the UK goes to the polls, the picture is still unclear as to who will be running the country in the coming days," said analyst Alastair McCaig from IG. McCaig said the latest IG general election binary is currently showing a 94% chance there will be no majority government.Corporate earnings were mostly well-received by investors on Wednesday, with blue chips Sage Group, Imperial Tobacco, Legal & General and GKN all impressing, though Sainsbury's disappointed with its first annual loss in a decade.Stocks had temporarily dropped into the red before the close following a weak start on Wall Street after Yellen warned of the "dangers" in an environment of elevated stock markets and low interest rates. Equity valuations are "generally quite high", the Fed chair said, and there could be a large increase in long-term rates when the Fed eventually tightens policy.Economic data in focusService-sector from across the globe was also on investors' minds on Thursday, along with labour-market figures in the States.The Markit/CIPS UK services purchasing managers' index (PMI) rose to 59.5 in April from 58.9 a month earlier, more than the 58.5 predicted by analysts. The final reading of the Markit Eurozone services PMI was unexpectedly revised up to 54.1 from the 'flash' estimate of 53.7, more or less in line with the 54.2 level in March. Meanwhile, the HSBC Chinese services PMI rose to a four-month high of 52.9, up from 52.3 in March but slightly below expectations.The closely-watched ADP employment report showed just a 169,000 increase in US private payrolls in April, compared with a revised 175,000 reading in March and well below the 200,000 consensus forecast.While it is only seen as a very rough guide to official US non-farm payrolls data, the weak figure may temper some optimism surrounding the government data due on Friday. Analysts currently predict the non-farm payrolls to jump 230,000 in April, from 126,000 the month before.Earnings impress but Sainsbury's bucks the trendSainsbury's fell sharply after reporting a loss for the full year, though results still came in ahead of analysts' expectations. The grocer reported a loss before tax of £72m for the year ended March, compared with a £898m profit previously, prompting it to slash it full-year dividend by 23.7%.After an early fall, software company Sage surged after saying it's on track to meet 2015 targets, as it reported a 6.2% rise in organic revenue for the first half of this year.Imperial Tobacco gained after lifting its dividend 10% as its growth brands delivered strong growth and earnings beat expectations in the first half. Adjusted earnings per share were up 4% to 93.3p.Legal & General also impressed with an 8% increase in first-quarter net cash generation to £326m, while annuity sales jumped 19%.Engineering giant GKN was in demand after saying it still expects growth in 2015 as a strong automotive performance drove a 1% increase in organic sales in the first quarter.Vodafone was also making decent gains after Exane BNP Paribas raised its rating on the stock to 'outperform' and lifted its target price from 220p to 270p. The broker said: "There are much better times ahead in our view." Market MoverstechMARK 3,193.99 +0.64%FTSE 100 6,933.74 +0.09%FTSE 250 17,412.08 -0.23%FTSE 100 - RisersSage Group (SGE) 536.00p +7.96%St James's Place (STJ) 886.50p +1.84%Imperial Tobacco Group (IMT) 3,175.00p +1.76%Vodafone Group (VOD) 232.20p +1.60%Mondi (MNDI) 1,311.00p +1.55%International Consolidated Airlines Group SA (CDI) (IAG) 545.00p +1.49%Centrica (CNA) 260.20p +1.40%Dixons Carphone (DC.) 431.10p +1.22%BT Group (BT.A) 454.30p +1.14%Capita (CPI) 1,173.00p +1.12%FTSE 100 - FallersAberdeen Asset Management (ADN) 431.10p -4.33%Sainsbury (J) (SBRY) 266.30p -3.16%Hikma Pharmaceuticals (HIK) 1,980.00p -2.17%Antofagasta (ANTO) 782.50p -2.00%London Stock Exchange Group (LSE) 2,436.00p -1.66%3i Group (III) 485.30p -1.54%Randgold Resources Ltd. (RRS) 4,914.00p -1.54%British Land Company (BLND) 805.50p -1.35%Carnival (CCL) 2,903.00p -1.29%Glencore (GLEN) 310.45p -1.24%FTSE 250 - RisersSupergroup (SGP) 1,071.00p +7.42%Aveva Group (AVV) 1,875.00p +7.14%Evraz (EVR) 205.70p +5.81%Ocado Group (OCDO) 375.10p +5.45%Soco International (SIA) 197.70p +4.00%Wetherspoon (J.D.) (JDW) 764.50p +3.87%Ted Baker (TED) 2,962.00p +3.57%Marston's (MARS) 169.20p +3.55%Millennium & Copthorne Hotels (MLC) 600.50p +3.27%Premier Oil (PMO) 184.90p +3.07%FTSE 250 - FallersGenus (GNS) 1,274.00p -7.95%Diploma (DPLM) 758.50p -7.05%Man Group (EMG) 172.90p -5.78%PayPoint (PAY) 799.50p -5.27%AL Noor Hospitals Group (ANH) 855.50p -5.16%AO World (AO.) 172.50p -4.17%Brown (N.) Group (BWNG) 322.10p -3.85%Kaz Minerals (KAZ) 259.30p -3.82%Centamin (DI) (CEY) 61.90p -3.81%Allied Minds (ALM) 620.00p -3.50%