Stock index futures signal gains for Wall St

* After markets closed on Wednesday, ratings agency Moody's warned that the United States could lose its top credit rating if lawmakers fail to increase the country's borrowing limit, sending U.S. stock index futures sharply lower.

* Moody's said it would likely assign a negative outlook to the nation's gold-plated credit rating if a credible agreement with long-term deficit reduction measures was not achieved.

* President Barack Obama clashed with Republican lawmakers on Wednesday in a fierce White House meeting on deficit reduction that left a deal in question as the clock ticked toward a debt default.

* Shares on Wall Street ended higher on Wednesday on expectations further stimulus measures could be on the horizon after Federal Reserve Chairman Ben Bernanke said the Fed is ready to ease monetary policy further if economic growth and inflation slow much more.

* JPMorgan will be the first big bank to report quarterly earnings, with Wall Street likely to pay more attention to its forecasts than the earnings, looking for clues on the direction of the U.S. lending business. Analysts expect the firm's earnings per share (EPS) to rise to $1.21 in the second quarter from $1.09 a year ago.

* Google is expected to report a rise in earnings per share to $0.71 from $0.68 a year earlier. Its newly released social networking service, dubbed Google+ will be in the spotlight.

* Shares of Yum! Brands rose 2.2 percent in extended trading as the fast-food firm raised its full-year earnings forecast after China helped deliver quarterly earnings for the company that topped Wall Street's forecast.

* Marriott International Inc fell more than 4 percent in after-hours trading as the hotels firm reported higher quarterly earnings that matched analyst estimates and gave a tepid forecast for the year.

* Amazon.com Inc will launch a tablet computer this year to extend its position as the world's largest Internet retailer, expand in mobile commerce and sell more digital goods, according to analysts and investors.

* U.S.-based mining equipment maker Joy Global Inc is in talks to buy International Mining Machinery Holdings Ltd <1683.HK>, a maker of coal-mining equipment in China, a source familiar told Reuters, in a deal which could keep Caterpillar from gaining further scale in China.

* In Europe, the pan-European FTSEurofirst 300 index of top shares was lower in early trade, on the back of Moody's warning on the credit rating of the United States.

(Reporting by Harpreet Bhal; Editing by Hans-Juergen Peters)