Fitch Ratings has a warning for U.S. policy makers: Work hard on fiscal policy, or another downgrade of the U.S. credit rating is definitely foreseeable, the Wall Street Journal reported.

An executive with Fitch told lawmakers the ratings firm will downgrade the country's triple-A credit rating.

A downgrade would shock the markets in a fashion similar to Standard & Poor's downgrade of the U.S. sovereign credit rating last summer. At the time, S&P slashed the nation's triple-A credit rating to double-A plus.

Fitch and Moody's Investors Service remained committed last summer to keeping the U.S. credit rating at triple-A, but that has since changed.

News that Fitch is now looking at the possibility of a downgrade comes at a time when policymakers are anticipating a confluence of dangerous changes in early 2013—namely an end to the payroll tax holiday, the Bush tax cuts and automatic spending cuts.

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