The ripple effect of United Kingdom’s unexpected Brexit vote has stretched to the financial sector.

Last Friday, credit rating institution Moody’s lowered the credit rating for UK from stable to negative to negative—something that could possible lead to lower ratings for the sovereign in the future.

UK’s growth prospects, according to Moody’s, would be “materially weaker” if the government fails “to secure a favorable alternative trade arrangement with the EU and other countries.”

“During the several years in which the UK will have to renegotiate its trade relations with the EU, Moody’s expects heightened uncertainty, diminished confidence and lower spending and investment to result in weaker growth,” the credit rating service said.