Fund manager Aberdeen was a heavy faller on the FTSE 100 on Friday after a ratings downgrade by Morgan Stanley from 'equal weight' to 'underweight'. The target price for the stock has been slashed from 492p to 393p.The bank said that a "deteriorating" fund performance at Aberdeen compounds challenging fundamentals in the emerging markets (EM).This "increases the risk of negative revisions and further multiple de-rating" for the stock, it said.Morgan Stanley said that it continues to avoid "EM-centric" fund managers and instead prefers sector peer Schroders given its focus on the developed markets and multi-asset offering.Aberdeen was trading 4.5% lower at 402.5p by 09:31 on Friday, while Schroders was down just 0.3%.BC