Greece has been living on foreign debt for the last several years and the country was able to borrow loans from other countries and global banking majors at very low cost. The financial crisis since 2008 has made lenders sit and review their lending practices.
Suddenly the entire group of lenders realized that Greece is living on abnormal debt levels and it may not be able to repay the loans at the current GDP levels. So the Greece credit rating got revised downward to negative few months back, post which Greece is unable to borrow money at low cost.
The European Union gave verbal commitment on some funding to Greece few weeks back, but nothing has happened as of now. So the Greek government is unable to borrow at very high cost which it also knows is unsustainable. So it is most likely to go for IMF funding in the near future, aver experts.