Standard & Poor's downgraded its long-term credit rating on Europe's rescue fund to double-A-plus from triple-A, following its move on Friday to lower ratings on nine eurozone countries.

Uncertainty about the triple-A rating on the bailout fund, known as the European Financial Stability Facility, had been growing since the sovereign-debt crisis in Europe escalated last summer. S&P warned in early December that an EFSF downgrade would likely follow any adjustment to the credit ratings of the eurozone countries that guarantee the fund. France, which lost its triple-A rating from S&P on Friday, is the fund's number two guarantor.