Advertising giant WPP was the biggest loser on the Footsie this morning after Citigroup warned that now is not the time to buy.

The big-hitting broker has cut the rating on Sir Martin Sorrell's company from buy to hold and slashed its price target from 552p to 440p.

WPP shares dropped 6p to 3971/2p in a widely higher London market after analysts said the seasonal nature of the business, with the last three months of its year proving its most profitable thanks to a Christmas advertising rush, means it no longer thinks clients should snap up the stock.

But they reckon its agency business model is better-suited now to a recession than ever before, and that its aim to keep margins flat is not outlandish.

The FTSE 100 jumped 65.28 points to 3908.13 as investors' mood was lifted by expectations of an announcement today on US banks' toxic debts. But volumes were likely to be low as traders sat on their hands waiting to hear Treasury Secretary Timothy Geithner's plans.

Financial stocks were the biggest winners, with insurer Old Mutual adding 4p to 47.8p, Barclays recovering from Friday's sell-off to trade up 7.8p at 112.8p and Legal & General gaining 2.7p to 45.5p.

Property companies' dash for cash once again put them in the spotlight. Hammerson dipped 1/2p to 2701/2p despite the Brent Cross shopping centre owner reporting a 98.6% take-up of its rights issue. Like many of its rivals, it is looking to reduce its debts and boost its balance sheet. The rump of 5.8 million shares will now be sold off by the underwriter.

Competitor British Land slid 13/4p to 3731/2p after UBS cut its rating on the shares from buy to neutral. Analysts say that the added security against a further fall in the value of its landbank that its recent cash call has given has now been priced into the shares. However, UBS has lifted its price target for the stock from 335p to 370p — still below the price they were changing hands for today.

Royal Bank of Scotland, the largely state-owned lender, gained 1p to 25p on reports that Aussie banking group ANZ may be interested in its Asian retail and commercial banking business. HSBC, Standard Chartered and a number of Chinese banks have also been mooted as potential suitors.

AIM pharmaceuticals tiddler SkyePharma marked time at 157p after saying it had filed a new drug application for Flutiform, its main asthma treatment, with the US Food and Drug Administration.

Asian stocks climbed overnight on the back of growing optimism that the US's government's latest plans to stabilise financial markets would succeed. In Tokyo, banks were among the biggest risers — with top lender Mitsubishi UFJ up almost 5% to 512 yen after it said it was closing 50 branches and cutting 1000 jobs to streamline its operations. Rivals Mizuho Financial Group gained 5.3% to 220 yen and Sumitomo Mitsui Financial Group soared by 7.3% to 1323 yen.

The Nikkei 225 hit a seven-week high, closing 269.57 points higher at 8215.53.

Exporters also benefited from the weaker yen. The gains came despite a survey that showed big Japanese manufacturers have become gloomier about trading conditions as demand sinks.

Hong Kong's Hang Seng index jumped 613.91 points to 13,447.42 after earlier hitting a five-week high. Commodity stocks were big winners on the back of higher oil and metals prices.