WPP's share price was performing well on Thursday after UBS increased its target for the stock from 1,300p to 1,500p and raised its growth forecasts on the back of an optimistic outlook for the advertising and media giant.The bank has lifted its organic growth forecast for 2013 from 3.2% to 3.3% and for 2014 from 4% to 4.5%. Over the medium term, growth is now expected to be 3% compared with its previous 2.5% estimate. "We argue that corporates will increase their investment in the services WPP provides to drive their top-line growth and gain market share in the US and Europe, improve branding in Asia and that Media, Digital and Data will see cyclical and structural growth, combining to deliver strong execution of WPP's strategy."UBS said its believes that management will deliver on its target of margin expansion of 50 basis points in 2013 and beyond, but said that upside to this guidance is limited given the expected continued investment in the business. While the company has played down recent speculation about potential mergers and acquisitions, it has stated that cash returns through higher dividends and a potentially higher share buyback are the key focus. This "align[s] strategy with shareholders' interests and further underpin[s] the investment case", UBS said.The bank highlighted that WPP is trading on 14.7 times 2014 estimated earnings, compared with sector peer Publicis which trades at a multiple of 17. It said: "Given the stronger growth and margin expansion visibility we prefer WPP and reiterate our 'buy' rating."The stock was 0.78% higher at 1,365.53p by 10:53 on Thursday.BC