Numis Securities is telling investors to top up on shares in pub landlord and brewer Greene King.The broker has upgraded Greene King to 'buy' from 'add' with a 975p target price, praising the company's long-term strategy and pointing to recent share price weakness as a buying opportunity."We are upgrading to 'buy' to reflect faster expansion and progress with the company's repositioning towards food-led managed pubs," Numis said in a note ahead of Greene King's first quarter update on 10 September.Nevertheless, Numis expects Greene King's growth to be muted in 2014/15, saying it faces an uphill task to match last year's performance, particularly in the first quarter.It pointed to figures showing like-for-like sales in its managed pubs rose just 1.1% in the first eight weeks of the new financial year"Although this summer has been good, May-July experienced 4% less sunshine and 7% more rainfall than last year," Numis said.Shares rose 10.5p or 1.2% to 815.5p at 16:22 in London.PW