Other risks to global ratings cited by Fitch included the 50 percent fall in the price of crude oil seen since June last year. While this has spurred consumer spending in oil-importing developed countries, it has hit the revenues of energy-producing companies and countries.
"The largest financial impact is being felt across a disparate group of energy-producing sovereigns, corporates and public finance issuers whose forecast revenue streams have been cut substantially as oil prices have fallen to around $50 per barrel," it said.
Fitch also flagged the impact of the emerging market slowdown, which it described as "primarily due to the structural adjustment in China and recession in Russia and Brazil."
It forecast that economic growth in emerging markets would average 3.6 percent in 2015, down from a peak of 6.9 percent in 2010.
"The strong U.S. dollar and higher U.S. interest rates could also expose other emerging-market vulnerabilities, such as high leverage, weak policy frameworks and political fragilities, so the risks for emerging markets are increasing," Fitch said.