A looming US government shutdown threatens the economy, but probably won’t challenge the country’s sovereign debt rating, said Joydeep Mukherji, managing director at S&P Global Ratings.

In contrast with the US government debt-ceiling impasse earlier this year, “a shutdown does not raise the risk of an event of default,” said Mukherji in an email. “Such an outcome would affect economic activity but is not likely to have an impact on the sovereign rating.” S&P released a report on the impact of the shutdown for the US public finance sector on Friday.

If a shutdown begins on Oct. 1, S&P expects “the federal government will continue to provide essential services and meet its spending commitments (including paying for debt service) that do not rely on annual budgetary appropriations from Congress,” Mukherji said.

In Friday’s report, S&P said the company doesn’t expect a short shutdown of a few weeks to result in credit pressures for US public finance issuers. The agency did warn that a lengthy furlough for the government “could introduce credit pressures as funding and reimbursement delays flow down to public finance entities that lack liquidity and other revenue sources.”

In March as the latest debt ceiling tussle loomed, S&P Global Ratings said in a statement it “could lower the rating over the next two to three years if unexpected negative political developments weigh on the strength of American institutions and the effectiveness of long-term policymaking or jeopardize the dollar’s status as the world’s leading reserve currency.”

At the time S&P affirmed its ‘AA+’ long-term and ‘A-1+’ short-term unsolicited sovereign credit ratings on the US. The outlook on the long-term rating remained stable.

Earlier this week, Moody’s, the only remaining major rating agency to retain the US as a Triple A credit signaled that any shutdown “would underscore the weakness of US institutional and governance strength relative to other Aaa-rated sovereigns.”

(Updates with details from S&P report in fourth paragraph.)