Better-than-expected economic data and improving optimism surrounding Greece strengthened stock markets on Tuesday morning, with sentiment also lifted by a raft of broker upgrades.The FTSE 100 was trading 0.25% higher at 6,842.53 by midday with Sports Direct, Smith & Nephew, Johnson Matthey, Diageo and Vodafone being lifted by analysts' comments.Meanwhile, Ladbrokes was leading gains on the FTSE 250 after confirming merger plans with Gala Coral.Hopes over a short-term funding deal for Athens picked up on Monday following a last-minute proposal by Greece's government at the weekend, propelling the FTSE 100 1.7% higher.While an emergency EU summit failed to result in a new cash-for-reforms agreement, leaders expressed hopes that a deal will be struck this week."European stocks are still reacting favourably to Greece's latest set of reform proposals that creditors have described as having the first meaningful concessions in months," said CMC Markets analyst Jasper Lawler.Data tops forecastsA series of global purchasing managers' indices from across the board came in ahead of expectations on Tuesday.Overnight, the HSBC China manufacturing PMI improved to 49.6 in June from 49.2 in May, showing that activity contracted at a slower rate than the 49.4 consensus forecast suggested.PMIs from across Europe also beat estimates, with activity in Germany and France picking up more than analysts expected. As a result, the Markit Eurozone composite PMI rose to 54.1 in June from 53.6 previously, surpassing the 53.5 estimate.US durable goods orders, US new home sales and the Markit US manufacturing PMI will also be released during the session.Ladbrokes jumps on Gala Coral dealLadbrokes shares jumped 15% after the bookie chain confirmed it was in mergers talks with the board of Gala Coral. The tie-up would create a the UK's largest bookmaker with over 4,000 betting shops nationwide.A number of blue chips were also performing well after a series of broker upgrades. RBC Capital Markets lifted its stance on Sports Direct to 'outperform', saying the sports retailer is "regaining momentum".UBS raised Smith & Nephew to 'buy', pointing out the shares were trading at a discount to the European medical technology sector.Johnson Matthey rose after Citigroup upgraded the chemical business to 'buy', saying the current valuations is "an attractive entry point".Nomura lifted Diageo to 'buy', saying bad news flow at the spirits product is abating and "a recovery in growth should become visible in full-year 2016".Meanwhile, Vodafone's share price was also boosted by an upgrade by Nomura from "buy", saying that the proposed asset swaps with Liberty Global could lead to a "golden opportunity".In other news, distribution and outsourcing business Bunzl disappointed with a slowdown in organic growth in the second quarter. The group also announced that it has acquired four businesses in the US, Colombia, Canada and France.Oilfield services outfit Petrofac gained after saying that additional costs tied to the development of its flagship project in the Shetland Islands would be partially offset by tax provisions. Charles Stanley upgraded the stock to 'accumulate', saying there is "hope that Petrofac will turn a corner".Market MoverstechMARK 3,220.76 +0.71%FTSE 100 6,842.53 +0.25%FTSE 250 17,979.04 +0.41%FTSE 100 - RisersSports Direct International (SPD) 725.50p +3.27%Smith & Nephew (SN.) 1,116.00p +2.67%Meggitt (MGGT) 480.00p +2.65%Johnson Matthey (JMAT) 3,219.00p +2.09%Diageo (DGE) 1,944.50p +1.97%Hikma Pharmaceuticals (HIK) 1,945.00p +1.78%Weir Group (WEIR) 1,816.00p +1.74%Marks & Spencer Group (MKS) 558.50p +1.73%Sage Group (SGE) 549.00p +1.57%easyJet (EZJ) 1,607.00p +1.39%FTSE 100 - FallersBunzl (BNZL) 1,864.00p -1.43%Anglo American (AAL) 981.10p -1.41%Rio Tinto (RIO) 2,737.00p -1.19%BHP Billiton (BLT) 1,334.00p -0.93%TUI AG Reg Shs (DI) (TUI) 1,170.00p -0.85%Glencore (GLEN) 271.65p -0.71%Associated British Foods (ABF) 3,073.00p -0.68%Royal Dutch Shell 'A' (RDSA) 1,862.50p -0.67%Severn Trent (SVT) 2,164.00p -0.55%Royal Dutch Shell 'B' (RDSB) 1,893.00p -0.50%FTSE 250 - RisersLadbrokes (LAD) 140.60p +15.15%Petrofac Ltd. (PFC) 926.50p +6.56%Serco Group (SRP) 131.40p +6.40%Telecom Plus (TEP) 843.00p +2.68%Hunting (HTG) 640.00p +2.65%Greene King (GNK) 856.00p +2.52%TalkTalk Telecom Group (TALK) 399.70p +2.38%Vesuvius (VSVS) 428.60p +2.07%Ocado Group (OCDO) 402.60p +1.95%Michael Page International (MPI) 550.50p +1.94%FTSE 250 - FallersLonmin (LMI) 125.00p -3.10%Jimmy Choo (CHOO) 157.50p -2.78%Foxtons Group (FOXT) 255.60p -2.59%Evraz (EVR) 143.20p -2.45%Polymetal International (POLY) 537.00p -2.36%AO World (AO.) 144.00p -2.04%Acacia Mining (ACA) 300.60p -1.76%Wizz Air Holdings (WIZZ) 1,590.00p -1.73%Just Retirement Group (JRG) 178.00p -1.66%Mitchells & Butlers (MAB) 467.40p -1.66%