S&P Global Ratings on Friday moved its outlook on the U.K.'s AA sovereign credit rating to "negative" from "stable," citing concerns about the country's fiscal outlook. The British pound /zigman2/quotes/210561263/realtime/sampled GBPUSD +0.0164% tumbled and yields on British government bonds, or gilts, soared after Treasury chief Kwasi Kwarteng on Sept. 23 unveiled a mini-budget plan that included 45 billion pounds in unfunded tax cuts. The Bank of England this week stepped in to buy gilts in an effort to stabilize the bond market. S&P, in a statement, said it now expects the U.K. government deficit to widen by an average 2.6% of gross domestic product annually through 2025, while net general government debt will continue on an upward trajectory, "in contrast to our previous expectation of it declining as a percentage of GDP from 2023." The ratings firm said the U.K. "continues to face balance-of-payment risks stemming from its persistently large current account deficit, which we forecast will widen to 6% of GDP this year, in part driven by higher costs of energy imports."