Korea Bonds and the Bank of Korea: KTBs and Won — 2026-09-04

Top developments

3-Year KTB Yield Hits 3.93% as Global Rates Spike

On September 2, 2026, Korea’s 3-year treasury bond yield rose 5.2 basis points to close at 3.93%, approaching its yearly high of 3.959%. This surge was primarily driven by the US 10-year Treasury yield nearing 4.8%, raising fears that domestic mortgage rates could climb toward 8%. The widening spread between Korean and US yields is squeezing borrowers and complicating the Bank of Korea’s monetary policy path.

30-Year Yields Jump 10bp on Issuance Concerns

The 30-year government bond yield surged 10 basis points on September 1, marking its largest single-day rise in three months. Analysts attribute this spike to concerns over the government's plan to issue up to 222.8 trillion won in bonds in 2027, combined with the immediate burden of recent auctions. The sharp move in long-dated bonds has widened the term premium, signaling market anxiety about fiscal expansion and supply pressure.

Foreign Investors Turn Net Sellers of KTBs

For the first time since South Korea’s inclusion in the World Government Bond Index (WGBI), foreign investors recorded a net sale of $96 million in South Korean government bonds in July. This reversal comes despite earlier expectations of sustained passive inflows. The shift suggests that global rate volatility and the strong dollar may be outweighing the structural benefits of index inclusion in the short term.

FX Reserves Hit Record High on Bank Deposits

South Korea’s foreign exchange reserves rose by a record $14.33 billion in August, driven largely by an increase in commercial banks’ foreign-currency deposits at the central bank. This influx helps stabilize the won but also reflects heightened caution among financial institutions amid global market volatility. The reserve build provides the Bank of Korea with additional buffer against external shocks.

Local view

Local media highlight the "tipping point" risk for Korean bonds. Seoul Economic Daily notes that market rates are likely to keep rising due to the Bank of Korea's hawkish stance and a widening term premium. Money Today reports that domestic investors are shifting into ultra-short bond funds, which attracted 648 billion won in inflows while broader bond funds saw outflows, indicating a defensive duration strategy. E-Today emphasizes that the 30-year yield surge was exacerbated by both auction burdens and the shock of next year's large issuance plans.

Context & numbers

• 3-Year KTB Yield: 3.93% (as of Sept 2, 2026)
• 10-Year KTB Yield: 4.418% (up 4.7 bps on Sept 2)
• Household Debt: Topped 2,000 trillion won, with mortgage rates reaching as high as 7.12%.
• FX Reserves: Increased by $14.33 billion in August 2026.
• Bank Holdings: Top four banks increased corporate bond holdings by 4.9 trillion won in H1 2026 as AAA yields topped 4%.

On the radar

• WGBI Liquidity Measures: The Ministry of Economy and Finance is issuing 500 billion won in seasoned KTBs via non-competitive bids to boost liquidity following WGBI inclusion.
• Foreigner Guidebook: The Korea Securities Depository released a guide for foreign investors on utilizing Korean government bonds as collateral, aiming to support post-WGBI integration.
• Next BOK Meeting: Market participants are watching for further guidance from the Bank of Korea, with the base rate currently at 3.00% after the August hike.