US Markets

Stock futures rise further as GDP above estimates

U.S. stock-index futures rose further and Treasuries declined after data showed the U.S. economy grew 4 percent in the second quarter, with the better-than-expected report coming ahead of a monetary-policy decision from the Federal Reserve.

Stocks futures added to gains after the GDP report, which exceeded expectations of a 3.2 percent annualized growth rate and also had the Commerce Department revising its take on the first quarter, which it now figures contracted 2.1 percent versus its initial 2.9 percent contraction.

The yield on the 10-year Treasury yield used to figure mortgage rates and other consumer loans jumped 5 basis points to 2.508 percent.

Read MoreUS growth surges by 4 percent after a frost first quarter

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ADP reported the private sector added 218,000 jobs in July.

Analysts had expected the U.S. economy to have grown by an annualized 3.2 percent between April and June, following the 2.9 percent decline in the first three months of the year.

The Fed is seen reducing its asset purchases by another $10 billion to $25 billion a month.

"GDP is actively watched by the Federal Open Market Committee (FOMC) and if the figure is growing at a rate higher than official estimates, chatter of rate rises will hit the Street," said Evan Lucas, market strategist at IG, in a note.

US GDP to be above 3% in Q2 after 'lousy' Q1: Pro

Sprint gained after the telecommunications company reported better-than-expected second-quarter revenue.

Goodyear Tire and SodaStream will post numbers after the market close.

Twitter's stock jumped nearly 30 percent in after-hours trading on Tuesday following the release of its quarterly earnings, as solid growth in active users soothed concerns about the future of the microblogging site.

Other stocks to watch include McDonald's. Its Tokyo shares declined nearly 3 percent after McDonald's Japan withdrew its profit forecasts on the back of China's meat scandal.

On Tuesday, President Barack Obama announced an expansion in sanctions on Russia, targeting its energy, defense and financial sectors. His statement came after the European Union said it was increasing its own sanctions against Russia after the country continued to support separatists in eastern Ukraine and build up armed forces on its border with Ukraine.

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Concerns over Argentina and the prospect of it defaulting for the third time in 28 years were also in focus. The government and holdout creditors will resume talks on Wednesday to try and avert a debt default by the end of the day.

Japan's benchmark Nikkei index scaled a new six-month peak on Wednesday, despite the release of disappointing data. Industrial output dropped 3.3 percent in June from May, significantly below forecasts and marking the first decline in two months.