U.S. stock futures fell, indicating the Standard & Poor’s 500 Index may halt its longest advance in 20 months, as slowing growth in Japan fueled concern the global economy is worsening.

Citigroup Inc. (C), the third-largest U.S. bank by assets, lost 0.9 percent in German trading. Biogen Idec Inc. (BIIB) retreated 0.4 percent after Elan Corp. said it will not try to prevent a takeover by the company. Google Inc. (GOOG) added 1.6 percent after a person familiar with the matter said it plans to cut about a fifth of the staff at its Motorola Mobility Holdings Inc. unit.

S&P 500 futures expiring in September lost 0.1 percent to 1,400.8 at 10:44 a.m. in London. The benchmark gauge on Aug. 10 completed its longest rally since December 2010 amid speculation the Federal Reserve may introduce further stimulus measures. Dow Jones Industrial Average futures declined 10 points, or 0.1 percent, to 13,162 today.

Japan’s gross domestic product rose at an annualized pace of 1.4 percent in the three months through June, compared with 5.5 percent in the previous quarter, according to a report from the country’s Cabinet Office. That was a slower pace than the median estimate of 2.3 percent in a Bloomberg News survey of economists.

Citigroup dropped 0.9 percent to $28.63 in German trading.

Biogen, which markets a multiple-sclerosis drug with Elan, slipped 0.4 percent to $144.87. Elan’s Chief Executive Officer, Kelly Martin, said he won’t use a poison pill or another form of defense to stop Biogen from taking over the business.

Michael Yee, an analyst at RBC Capital Markets, wrote in a report on July 25 that Elan might consider selling itself to Biogen if its Alzheimer’s treatment failed. The Irish company’s partners subsequently abandoned most of their plans to jointly develop the drug.

Google gained 1.6 percent to $652.50 in early New York trading after a person familiar with the matter said the owner of the world’s most popular search engine intends to cut about 4,000 jobs and shut down a third of the facilities at the Motorola Mobility unit.

To contact the reporter on this story: Namitha Jagadeesh in London at njagadeesh@bloomberg.net

To contact the editor responsible for this story: Andrew Rummer at arummer@bloomberg.net