Canaccord Genuity has upgraded its rating for AG Barr to 'buy' but downgraded its view on Britvic to 'sell' following the Competition Commission's (CC) provisional approval of the soft-drink companies' merger on Tuesday.Comments from Britvic Chairman Gerald Corbett - that the firm is in a "different place" to last summer when the company first agreed to a tie-up - are "perplexing", according to Cancaccord analyst Wayne Brown. He also said that remarks about the company performing better are "questionable" given a weaker performance in the second quarter.Investec has upgraded its rating for transport firm FirstGroup from 'hold' to 'add', saying that it is on the verge of becoming an interesting equity investment again."Whilst clarity on the rights issue take-up is not expected until the end of the month (dealings in the new shares start on June 26th), a properly funded group with cash generative activities should be a more attractive investment," said analyst John Lawson. He said that the group will shortly be putting its balance-sheet issues to bed.Panmure Gordon has hailed Keller's acquisition of North American Piling, but has kept its 'hold' rating for the FTSE 250-listed ground engineering specialist following a decent run this year."Fundamentally we are positive on the group's service offering and market positioning but with a full valuation and share price trading at two-year price/relative highs we thought the price had moved far enough. This explains our current 'neutral' stance."