South African government yields climbed and the rand pared an advance after the National Treasury said it will increase the amount of debt sold at weekly bond auctions to help fund a bailout of the State-owned electricity company and counter a tax revenue shortfall.

Starting on August 6, the National Treasury will sell R4.53-billion of fixed-rate debt per week, up from R3.3-billion, it said in a statement on Wednesday. Amounts at sales of inflation-linked bonds will rise to R1.04-billion from August 16, compared with R760-million currently.

While the additional borrowing was expected after the government announced another bailout for Eskom Holdings earlier this month, the amount of the increase caught some traders by surprise. The rise in government debt will put the country’s last remaining investment-grade rating, at Moody’s Investors Service, at risk at a time when foreign investors are selling the country’s bonds at an average rate of of R450-million a day.

“The increase in issuance levels is larger than what was expected,” said Lloyd Miller, a Johannesburg-based analyst at ETM Analytics. “This suggests that the budget shortfall may be much larger than expected and could be a result of both weaker revenue collection as well as increased spending to fund bailouts to Eskom and other State-owned companies.”

Yields on benchmark securities due 2026 rose three basis points to 8.34%, while those on generic ten-year securities pierced the key 9% level to trade around the highest level in about a month. The rand, which had gained as much as 0.5% on the day, pared the advance to trade flat against the dollar.

Finance Tito Mboweni said last week Eskom will get R26-billion this financial year and R33-billion in 2020 to help it remain solvent. The news came just five months after he announced a three-year, 69 billion-rand cash injection for the utility. Moody;s described the bailout as “credit negative,” and Fitch Ratings lowered its outlook on the country’s debt to negative, from stable.

In addition to raising auction amounts, the Treasury said it would cancel bond-switch auctions for the rest of the year while it reviews the switch program. It is also committed to shortening the average maturity of bonds sold at auctions, it said.