Numis Securities has upgraded bourses operator London Stock Exchange from 'hold' to 'add' after the company identified more cost savings from its recent acquisition of LCH.Clearnet."The strategic development of the LSE continues and we believe the LSE is well placed to take advantage of the globalisation of their businesses," Numis said.Hargreaves Lansdown Stockbrokers has hailed the recovery story at Aviva, but has said that the market is likely to maintain a cautious stance on the insurance stock after its recent rally."The company remains a work in progress - even though there is light at the end of the tunnel - and the general market view of the shares as a cautious buy is likely to remain intact following this update."Vodafone's shares were under pressure on Thursday after a Goldman Sachs downgrade and a target price cut from UBS.Goldman has cut its recommendation for the stock from 'buy' to 'neutral' and reduced its target for the shares from 270p to 240p ahead of the company's fourth-quarter results due out next week. Meanwhile, UBS kept a 'buy' rating, but lowered its target from 275p to 255p.Investec has kept a 'hold' rating on tour operator Thomas Cook, saying that near-term earnings risks are high after the company's first-half results. The broker said that UK summer trading "gives us a cause for concern" given that a strong summer is needed from the company if it is to meet the market's profit forecasts.Oriel Securities has reiterated a 'buy' rating for Dixons Retail, saying that the announced all-share merger with Carphone Warehouse should be seen as a positive for shareholders."At first glance, the benefits from the deal look positive, and accretive to earnings, raising the possibility of further shareholder returns, particularly as property losses and high coupon bonds unwind in the next three years," the broker said.BC