JOHANNESBURG (Reuters) – South African rand slumped to its weakest in 18 months on Friday as deepening worries about the coronavirus sent global financial markets into a tailspin, while fears over a possible sovereign rating downgrade by Moody’s added to the pressure.

At 0627 GMT, the rand traded at 15.6350 per dollar, 0.96% weaker than its close on Thursday. The currency was at its weakest since Sept. 5, 2018.

Government bonds also weakened, with the yield on the instrument due in 2026 rising by 17.5 basis points to 8.04%.

“It’s been a rough week for markets all round, as the global economy struggles to come to terms with the fallout of the COVID-19 virus and the ultimate fully fledged economic impact,” said Bianca Botes, treasury partner at Peregrine Treasury Solutions.

Hopes that the coronavirus outbreak could be contained in China have vanished this week as infections spread across the globe.

The rand has also come under pressure as some analysts predicted that proposed cuts to the public sector wage bill would not be enough to save the country’s investment-grade credit rating.

Finance Minister Tito Mboweni unveiled the plan to cut the public sector wage bill by 160 billion rand ($10.50 billion) in his budget speech on Wednesday.

Moody’s said on Thursday it sees “elevated” risks to the budget forecasts due to doubts over whether trade unions would agree to cutting the public sector wage bill and potential liabilities from struggling state companies.

Moody’s is the last of the big three ratings agencies to have South Africa in investment grade, and is scheduled to review that rating next month.

($1 = 15.2377 rand)