Citigroup has upgraded its rating for Guinness and Smirnoff owner Diageo from 'neutral' to 'buy' after a slight pull-back in the shares over the last month.Citi said that the stock's current valuation "doesn't reflect the attractions of the investment case: (1) resilient growth in the current weak emerging-market [EM] environment; and (2) significant long-term opportunities in EM."Panmure Gordon has hiked its target price for advertising and media group WPP and retained its 'buy' rating, saying that the firm is on track for a strong second half."We now upgrade our WPP target price to 1450p (from 1250p). We consider WPP is set fair for a strong H2 2013 (and beyond), taking into account strengthening revenue trends and more aggressive use of free cash flow," said analyst Alex DeGroote.Nomura has maintained its 'buy' rating and 60p target price for electrical retailer Dixons, saying that the company's core businesses are undervalued by the market.Alongside its first-quarter results, Dixons announced on Thursday that it was disposing of its Pixmania division and its Turkish arm to focus on its core. The closures costs were a lot less than Nomura had expected. It said: "Italy remains the last 'issue' to resolve, but until a deal can be reached, we note the business was slightly cash generative last year and so, in our opinion, is not a significant concern."BC