Standard & Poor's (S&P) affirmed the U.K.'s AAA credit rating on Friday. The outlook is negative.
According to S&P analysts, Britons will vote to remain in the European Union (EU).
"Our affirmation of the rating reflects our assumption that, by a small majority, the referendum will deliver a vote to remain in the EU", the agency said.
But S&P added that a possible leave weighed on Britain's creditworthiness.