* Global markets fall on credit jitters

* Bernanke, Paulson, Cox set to testify

* General Motors expected to unveil restructuring plan

* June's PPI, retail sales data on tap (Updates with details, updates prices)

By Ellis Mnyandu

NEW YORK, July 15 (Reuters) - U.S. stock index futures fell sharply on Tuesday as concerns about the credit crisis' impact on banks and other financial services companies curbed investors' appetite for riskier assets and sparked a global stock market slide.

Stocks fell in Asia and Europe. The euro surged to a an all-time high against the dollar, while oil prices headed back toward record territory. Investors gravitated to the relative safety of government debt.

Despite the U.S. government's efforts to calm markets with a rescue plan for mortgage finance companies Fannie Mae (FNM.N: Quote, Profile, Research) and Freddie Mac (FRE.N: Quote, Profile, Research), investors feared the credit turmoil may be escalating, raising risks for the U.S. economy and the global financial system.

Investors will focus on testimony of Federal Reserve Chairman Ben Bernanke before the Senate Banking Committee starting at 10 a.m. (1300 GMT).