European stocks and US index futures rallied after Citigroup Inc received a government guarantee on $306 billion of assets to help shore up investor confidence.

Deutsche Bank AG and Credit Suisse Group AG gained more than 7 percent as the US government also said it will inject $20 billion into Citigroup, whose shares lost 60 percent last week. Citigroup jumped 40 percent in German trading. Commodity producers followed metals prices higher, while oil companies climbed after trading at their cheapest on record.

Europe's Dow Jones Stoxx 600 Index added 3.7 percent to 188.95 at 10:25 am in London as all 19 industry groups increased except for auto-related shares. Futures on the Standard & Poor's 500 Index added 1.9 percent.