Fitch Ratings is lowering its outlook for the United Kingdom, indicating a ratings downgrade may be coming.

The rating agency said Wednesday that while the U.K. is well-positioned now, it has very limited ability to absorb any further economic shocks stemming from the European economic crisis.

Fitch affirmed its “AAA” investment grade ratings for the UK’s issuer default and country ceiling ratings. But it lowered the UK’s rating outlook to “Negative” from “Stable” and said there is a more than 50% chance of a downgrade over the next two years.

While market tensions in Europe have lessened some in recent months, Fitch says the crisis is not resolved and could intensify. That would put the UK at risk given its close trade and financial ties.