By Chuck Mikolajczak
NEW YORK (Reuters) - U.S. stock index futures edged lower on Tuesday, indicating the benchmark S&P index may fall for a third straight session after a warning from the IMF about global growth prospects.
* The International Monetary Fund cut its projected global output for 2012 to 3.3 percent from 3.5 percent in its latest world economic outlook, warning that a lack of action by policymakers in the U.S. and Europe to fix their economic problems could extend the current slump.
* The IMF warnings comes on the heels of a growth forecast cut for East Asia by the World Bank on concerns China's slowdown could last longer than expected.
* Investors were also eyeing a euro zone finance ministers' meeting and a visit by German Chancellor Angela Merkel to Greece for any signs of progress in dealing with the region's debt crisis.
* On Monday, the euro zone finance ministers and the International Monetary Fund held a "thorough and robust" debate on Greece, but failed to make significant progress in deciding how best to get the country back on track with its bailout program.
* S&P 500 futures slipped 0.2 point and were slightly below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures shed 6 points, and Nasdaq 100 futures dipped 8 points.
* Earnings season gets underway in the United States when Dow component Alcoa Inc
* Analysts forecast third-quarter earnings of Wall Street's S&P 500 <.SPX> companies would fall 2.3 percent from the year-ago quarter, according to Thomson Reuters data, which would be the first drop in U.S. quarterly earnings in three years. According to the data, 91 companies in the S&P 500 have issued negative outlooks versus 21 positive pre-announcements, for a ratio of 4.3, the weakest showing since the third quarter of 2001.
* Recent earnings warnings from large multinationals such as FedEx Corp
* Edwards Lifesciences Corp
* European shares gave up early gains and turned negative as concerns over slowing global growth and its impact on corporate earnings weighed, although charts signaled a bounce back. <.EU>
* Asian shares rose but gains were moderated by concerns over global growth prospects, especially in China, and expected weak U.S. corporate earnings.
(Reporting by Chuck Mikolajczak Editing by W Simon)