UBS has lowered its recommendation for pharmaceuticals giant GlaxoSmithKline from 'buy' to 'neutral', saying that there's limited potential for further upside."Given GSK's valuation, and somewhat reduced earnings visibility for the stock, we see less scope for performance versus peers, and thereby downgrade GSK to 'neutral'."The target price for the stock has been reduced from 1,625p to 1,525p.While Investec has maintained its 'hold' rating for distribution and outsourcing group Bunzl, the broker says that company has once again delivered a strong trading performance."Whilst we regard Bunzl as a strongly managed business that will continue to deliver solid growth over the medium term, we believe that this is largely reflected in the current rating and therefore do not change our 'hold' recommendation," Morton said.Credit Suisse has highlighted Ophir Energy as its focus list stock in its sector review of oil and gas explorers and producers (E and Ps)."We continue to favour select E&P names in Europe. The emphasis is on the 'E' that provides for uncorrelated returns via the drillbit, as activity looks set to accelerate," the broker said.The broker has maintained its 'outperform' rating for Ophir, highlighting material near-term exploration programmes in Tanzania, Kenya and Gabon pre-salt as well as a strong balance sheet. It also reckons that Ophir remains a potential M&A candidate given the "strategic nature of its asset portfolio". BC