On Wednesday, global stock markets fell drastically after Fitch, a credit rating agency, lowered the United States’ long-term credit score. However, top economists say there’s no need for concern.

Fitch lowered the U.S. long-term foreign currency issuer default rating from AAA to AA+ on Tuesday night. They said this was due to a predicted worsening of the U.S.’s financial situation over the next three years, repeated political fights over the debt limit, and a generally increasing debt. This led to U.S. stock futures falling sharply, and it looked like the Dow Jones Industrial Average would drop nearly 300 points at the start of trading on Wednesday.

Stock markets in Europe and Asia also experienced heavy losses. But well-known economists, including former U.S. Treasury Secretary Larry Summers and Allianz’s Chief Economic Advisor Mohamed El-Erian, criticised Fitch’s decision. Summers called it “strange and clumsy,” and El-Erian was puzzled by its timing and logic. Current Treasury Secretary Janet Yellen called the downgrade “out of date.”

Alec Phillips, Chief Political Economist at Goldman Sachs, quickly pointed out that Fitch’s decision didn’t include any new financial information, so it wasn’t expected to affect the markets in the long term. Phillips also said that Fitch’s forecasts were similar to Goldman Sachs’ own and that the downgrade did not reflect new information or a major difference of opinion about the financial outlook.

Although this was the first downgrade of this type since 1994, another ratings agency, S&P, downgraded the U.S. rating in 2011. Despite causing a negative impact on the markets at the time, there was no evidence of forced selling, and the S&P 500 index recovered 15% in the following year.

Chris Harvey, Head of Equity Strategy at Wells Fargo Securities, echoed Phillips’ view, suggesting that any fall in stocks would be short-lived.

However, veteran investor Mark Mobius told CNBC on Wednesday that the downgrade might make investors reconsider their strategies on U.S. debt and currency markets. He suggested that investors might move away from the U.S. and into equities to protect themselves from any decline in the U.S. dollar or any other currency.

Virginie Maisonneuve, global Chief Investment Officer of equity at Allianz Global Investors, said that the market should be looking at other potential causes for a more extended downturn, like inflation and slowing growth.