Credit Suisse has maintained its long-term neutral rating for FTSE 100 speciality chemicals group Johnson Matthey but has given the stock a short-term buy trading call, recommending investors to build positions ahead of the full-year results on June 7th.The broker says that it prefers Belgian materials technology group Umicore in the long run but sees around a 12% potential upside to Johnson Matthey. In an earlier research report on Tuesday, the broker raised its target price on the stock from 2,350p to 2,400p.Peel Hunt has upgraded its rating for international publishing and events group Euromoney Institutional Investor from hold to buy and maintained its target price at 800p."Though results were in line and guidance on trading not significantly changed, we are upgrading by 6% this year at the EPS [earnings per share] line as the company enjoys a one-off credit at the CAP cost line and a 4% improvement on proposed tax rate," said analyst Malcolm Morgan.Canaccord Genuity has upgraded its rating for high street bakery and hot snacks chain Greggs now that 'pasty-gate' is over, saying that its target price of 520p now represents 12 per cent potential upside."The government's U-turn on the proposed pasty tax sees the removal of significant financial and strategic risk for Greggs. We did not change our forecasts when this proposal was announced (hence no change to our numbers today) but remain mindful that consensus estimates may rise with a number of other houses having downgraded on the back of the proposals back in March," said analyst Wayne Brown.BC