British bank Barclays had its rating downgraded to 'hold' from 'buy' over at Investec Securities on Wednesday.The broker said the main plank of its investment case for buying Barclays over the past year has been its extreme relative and absolute cheapness, reinforced by an absolute cost reduction story and the material FX tailwind in evidence in the Q3/Q4 2014 results, which Investec thinks, is likely to continue in 2015."However, (with Barclays) now trading on 0.9x 201 5/16 tangible net asset value, we think the valuation case is no longer overwhelming in the context of our deteriorating expectations for the scale and pace of return on equity recovery," said Investec.The broker also chopped its price target on Barclays to 270p from 295p.