Futures Hold Gains After Trade Deficit Report

U.S stock index futures were slightly higher Tuesday, ahead of the German constitutional court ruling on whether Germany may contribute to the euro zone's rescue fund and as investors hoped the Federal Reserve will announce further stimulus measures later this week.

Earlier, Germany’s Constitutional Court confirmed that the ruling on the permanent European bailout fund, the European Stability Mechanism (ESM), will take place Wednesdaydespite a new court challenge. European shares traded slightly lower.

Expectations have been growing that the central bank will launch another round of quantitative easing on the heels of some recent weak economic data, most notably last week's monthly jobs report. (Read More: How to Trade the Fed's Next Likely Move)

Meanwhile, ratings agency Moody's wanred that the U.S. could lose its triple-A debt ratingif next year's budget negotiations do not produce a downward trend in the country's debt to GDP ratio.

On the economic front, U.S. trade deficit increased in July to $42 billion, as exports to Europe felland imports from China surged to a new record.

McDonald's reported a weaker-than-expected 3.7-percent gain in August same-store sales, hurt by Europe and the volatile global economy.

Legg Mason said CEO Mark Fetting will resign at the beginning of next month named Joseph Sullivan interim CEO, as the money manager struggles with customer withdrawals.

Zynga announced its chief marketing officer Jeff Karp left the company on Monday, becoming the latest senior executive to leave the struggling social media gaming company.

Facebook CEO Mark Zuckerberg is scheduled to speak at the TechCrunch conference, in a rare public appearance since the social-networking giant's IPO in May. Since then, shares have plummeted nearly 50 percent amid heavy insider selling, ongoing controversy over the botched IPO and disappointing fundamentals.

The government will auction $32 billion in 3-year notes, with results available shortly after 1 p.m. New York time.

By CNBC’s JeeYeon Park (Follow JeeYeon on Twitter: @JeeYeonParkCNBC)

Coming Up This Week:

TUESDAY: 3-yr note auction, Intel developers forum
WEDNESDAY: Weekly mortgage apps, import & export prices, wholesale trade, oil inventories, 10-yr note auction, crop outlook report, Apple iPhone 5 event, FOMC meeting begins
THURSDAY: Jobless claims, PPI, 30-yr bond auction, FOMC mtg announcement, FOMC forecasts, Bernanke press conference; Earnings from Pier 1 Imports
FRIDAY: CPI, retail sales, industrial production, consumer sentiment, business inventories, FDA decision on Truvia

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