LONDON (ShareCast) - London's top stocks have moved into the blue with risers now appearing among the risers on a mixed day for the sector.

Kazakhstan’s ENRC and the South America-focused miner Antofagasta post healthy gains, but South Africa-focused miner Lonmin is among the bottom 10 as prices for the precious metal slip back. BHP Billiton is down despite receiving partial US anti-trust clearance to go ahead with its bid for rival miner Rio Tinto.

Engineering and project management firm AMEC is the biggest gainer. The group said it continues to make "excellent progress" as it raises its margin expectation to 6.5% for 2008. Previous expectations were of a 6% rise.

Advertising firm WPP revised £1.078bn bid proposal for Taylor Nelson has been rejected. The terms of the offer was 173p in cash and 0.1889 of a WPP share for each Taylor Nelson share. But Taylor Nelson said it has "unanimously rejected" the proposal, which it believes "again substantially undervalues" the group.

Pharmaceuticals firm Shire has made an agreed bid for Jerini, a German company that focuses on the discovery, development, and commercialisation of novel peptide-based drugs.

Supermarket giant Tesco is up slightly after Merrill Lynch upgraded the food retailer to buy from neutral but cut its target price to 395p from 440p. Marks & Spencer continues to yesterday’s slump after Goldman Sachs lowered it to neutral from buy.

Computer games retailer Game said it is performing slightly ahead of its expectations for the first half of the year as the PC and video games market has continued to grow strongly in period. “We look forward to the second half of the year and, although the quality of the first half release schedule is unprecedented, we remain confident about the key Christmas trading season,” it said.

Greene King announced underlying pre-tax profits of £142m for the 53 weeks to 4 May, up 2% on last year and slightly ahead of market expectations. Revenue was up 5% at £960.5m, with strong growth in food sales, which now account for 34% of sales. The full year dividend has been upped 14% to 26p.

Construction and housebuilding firm Galliford Try expects full year pre-tax profit to be in line with previous forecast of no less than £60m and doesn't expect to increase its full year dividend

Consumer electronics group Armour today warned that it expects results for the year to be 20% to 30% below current market expectations as consumers tighten their purse strings.

Altium Securities has double-upgraded its rating on the sports shop chain JJB Sports to ‘buy’ from ‘sell’ after the company’s share price fell heavily following Marks and Spencer’s announcement of a fall in like-for-like sales yesterday.

ABN Amro has lowered its rating on Yell Group to ‘hold’ from ‘buy’ and slashed its target price on the directories group to 70p from 335p.

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