Britvic shares are 'up with events' after a strong run, according to Investec which reiterated a 'hold' recommendation on the soft drinks group on Thursday."It has been a remarkable 2013 for Britvic, with its price looking set to close the year some 65% ahead," said analyst Nicola Mallard. "Opting not to merge with Barr, it is now implementing a new strategy alone. Cost reductions, if delivered and retained, should deliver some decent margin accretion."However, she said that the "real test of success" is if the company can consistently deliver profitable revenue growth - "something it has yet to prove".Mallard said that international development is progressing but is hard to value as it won't make a meaningful contribution to group results for the next two to three years. Nevertheless, she said that Britvic's Fruit Shoot drink is building a fan base in the US which could prove to be "game changing" at some point.Investec has revised its forecasts and valuation models, raising its target price for Britvic from 600p to 672p.The stock was trading 0.51% lower at 685p by 10:59.BC