(Adds details from Fitch statement)
NEW YORK, April 30 (Reuters) - Fitch Ratings on Thursday revised Bulgaria's credit outlook to negative from stable, saying the country's growing current account deficit raises concerns about its long-term external solvency.
"The deterioration in the global economic outlook increases the cost of implementing the economic adjustment needed to reduce the high current account deficit, adding to the downside risk for Bulgaria's ratings," Fitch's analyst Andrew Colquhoun said in a statement.
Bulgaria's current account deficit reached 25 percent of gross domestic product in 2008 -- the highest ratio of 80 emerging economies rated by Fitch -- and the global recession is further reducing the country's exports and capital inflows.
Moreover, Bulgaria cannot match currency devaluations in many neighboring countries as a result of a currency board arrangement which significantly limits monetary operations and leaves fiscal policy as the main tool to influence the economy.
Maintaining the currency board arrangement is key to Bulgaria's economic and financial stability, Fitch said, as the costs of abandoning it would be high given the "euro-isation" of the financial system.
Colquhoun said, however, that financial aid from the International Monetary Fund could "shore up the external finances and give breathing room for the macroeconomic adjustment."
Fitch rates Bulgaria's long-term foreign-currency debt at BBB-minus, the lowest investment-grade level. The country's long-term local-currency debt is rated BBB.
Supporting the ratings are Bulgaria's budget surpluses, which accounted for 3 percent of GDP in 2008, and the fact that outstanding sovereign eurobonds only mature in 2013 and 2015. (Reporting by Walter Brandimarte; Editing by James Dalgleish)