A funding squeeze threatens to cut U.S. oil output by as much as half a million barrels a day by the end of the year, with shale producers among the worst affected, Citigroup Inc. said. “Capital markets thus far have plugged shale’s funding gap but are showing signs of tightening, with impacts for drilling, oil supply and global prices,” Richard Morse and Ed Morse, analysts at Citigroup in New York, said in a note. Access to high-yield credit markets for debt-strapped producers is “sharply contracting,” they said. High-cost oil producers in the U.S. have been forced to scale back in the past year after members of the Organization of Petroleum Exporting Countries decided to maintain output to defend their market position. U.S. crude prices have dropped almost 40 percent since OPEC announced its policy change in November to trade at about $45 a barrel Wednesday. “The […]