Indonesia's 10-year government bond yield climbed to 7.71% on Oct. 29, its highest level since May 2020, after a poorly covered debt auction and a slide in the rupiah toward 18,200 per U.S. dollar raised the cost of financing Southeast Asia's largest economy.

The timing is awkward for the treasury, which still has more than a third of this year's borrowing to complete. A yield near 7.7% is about 80 basis points above the 6.9% the 2026 budget assumed, according to figures cited by Investortrust and Tradingpedia, which means every new bond sold from here costs the treasury more than planned.

The 10-year yield had risen 48.7 basis points in four weeks and 170.2 basis points over 12 months as of Oct. 29, Trading Economics data showed. A day earlier it had reached about 7.66%, then the highest since October 2022.

A thin auction at the Ministry of Finance

The clearest sign of strain came on Oct. 27. The Ministry of Finance's debt management office sold Rp20.65 trillion of government bonds across nine series, ANTARA reported, citing the office's statement. Total bids came to Rp31.09 trillion.

That fell well short of the Rp30 trillion indicative target, according to Investortrust, and compared with Rp35 trillion awarded and Rp64.9 trillion of bids at the previous auction on Oct. 13. Trading Economics put the drop in demand at 52%.

Investors who did bid asked for more. The government awarded Rp6.75 trillion of the FR0110 series, due May 2032, at a weighted average yield of about 7.38%, and Rp5.1 trillion of FR0111, due March 2037, at about 7.55%, ANTARA's table of results showed. It rejected every bid for a new three-month Treasury bill despite Rp3.61 trillion of demand.

The financing gap is large. Cumulative issuance through September reached Rp497.5 trillion, or 62.2% of the Rp799.5 trillion full-year target, leaving roughly Rp302 trillion to raise in the final quarter, Investortrust reported. The spread between Indonesian and U.S. 10-year yields widened to about 266 basis points, it said.

Analysts cited several drivers. Foreign investors have sold Indonesian equities since MSCI opened a consultation on whether to reclassify the market from emerging to "standalone" status, which sent the Jakarta Composite Index to its worst month since March 2020. Trading Economics also pointed to elevated U.S. yields, reports of a plan to extend free education through university, and September inflation of 3.28%, a three-month high partly driven by food prices. Investortrust added triple-digit crude oil prices.

Rupiah near 18,200 and Bank Indonesia's response

The currency has been under pressure for weeks. The rupiah fell back through 18,000 per dollar on Oct. 16, opening at 18,021, the day the stock market fell 8% at the open and trading was halted, ANTARA reported. The U.S. dollar reached a nearly five-month high of 18,223 rupiah on Oct. 27 before the rupiah firmed to around 18,127 on Oct. 29, according to Tradingpedia, on expectations of further central bank action. Investortrust put the rupiah at 18,175 during the Oct. 29 session.

Bank Indonesia has said it is defending the currency on three fronts: offshore non-deliverable forwards, spot and domestic non-deliverable forward trades onshore, and purchases of government bonds in the secondary market. Erwin Gunawan Hutapea, head of the bank's monetary and securities asset management department, told ANTARA on Oct. 16 that "interventions continue consistently" and that he expected portfolio outflows to persist as global risk-off sentiment lifted the dollar.

Governor Destry Damayanti said after a cabinet meeting at the presidential palace on Oct. 19 that the bank would stay in the market, and that hedging incentives introduced at the end of June had drawn about $8 billion to $8.5 billion of inflows through swaps and domestic forwards, ANTARA reported.

The bank's room to act is finite. Foreign exchange reserves stood at $146.3 billion at the end of September, according to ANTARA. At its Oct. 20-21 meeting the central bank held its benchmark BI-Rate at 5.75% and raised its deposit facility rate to 5%, according to the central bank's statement.

What bond investors are watching

Data released on Nov. 2 offered some relief: October inflation eased to 3.23%, Capital Times reported, giving the central bank less reason to tighten further on domestic grounds. The bigger test is the supply calendar. With about Rp302 trillion still to be sold before year-end, each of the remaining fortnightly auctions will show whether local banks and Bank Indonesia can absorb what foreign investors are no longer buying, and at what yield.

The first number to watch is Bank Indonesia's October reserves figure, which will show how much of the $146.3 billion in reserves the bank spent defending the rupiah during the month.