Fund manager Aberdeen fell sharply in today's session after receiving a ratings downgrade by Morgan Stanley to 'underweight'. The bank said that a deteriorating fund performance compounds challenging emerging-market fundamentals, 'increasing the risk of negative revisions and a further multiple de-rating at Aberdeen'.Airline operator IAG was also registering big falls, which is likely due in part to a continued decline by budget airline easyJet after its first-quarter update yesterday, which it said that losses in the first half would be worse than last year. HSBC lowered its rating on the company today to 'underweight'.Lloyds Banking Group was also heading lower after Investec cut its rating for the stock from 'buy' to 'hold', saying that expectations for 2013 are still "slightly frothy", causing the stock to slide lower. Royal Mail was also in reverse after underwhelming with a 2% rise in like-for-like revenue for the nine months ended December 29th. Head of Trading Joe Rundle from ETX Capital deemed the update "in line but an unexciting read on the whole".Meanwhile, both Randgold Resources and Fresnillo extended yesterday's surge, buoyed in part by continued rising precious metal prices. Randgold specifically was lifted by a reiteration of its 'buy' rating from Deutsche Bank. Sector peer Antofagasta was also a strong riser.Admiral was once again rising after what has been a choppy week for the motor insurer's share price. FTSE 100 - RisersRandgold Resources Ltd. (RRS) 4,300.00p +2.67%Fresnillo (FRES) 797.00p +2.18%Antofagasta (ANTO) 814.00p +0.87%BP (BP.) 491.30p +0.65%Admiral Group (ADM) 1,429.00p +0.63%RSA Insurance Group (RSA) 100.10p +0.35%Resolution Ltd. (RSL) 353.40p +0.28%Royal Dutch Shell 'A' (RDSA) 2,189.00p +0.27%Morrison (Wm) Supermarkets (MRW) 244.70p +0.20%Burberry Group (BRBY) 1,483.00p +0.20%FTSE 100 - FallersAberdeen Asset Management (ADN) 399.30p -5.24%International Consolidated Airlines Group SA (CDI) (IAG) 411.50p -3.72%Persimmon (PSN) 1,268.00p -3.21%Experian (EXPN) 1,088.00p -3.20%Prudential (PRU) 1,269.00p -3.13%Mondi (MNDI) 948.50p -3.12%Sage Group (SGE) 418.20p -3.06%Aggreko (AGK) 1,623.00p -3.05%Pearson (PSON) 1,160.00p -2.60%Ashtead Group (AHT) 778.50p -2.57%NR