State Bond Auctions in October 2026: 3, 10 and 20-year maturities

Key data

The Public Treasury activates in October 2026 a new financing round with four references of State Bonds covering the 3, 10 and 20-year tranches. The Resolution of September 25, 2026 from the General Directorate of the Treasury and Financial Policy sets the auction for October 1, with circulation on October 6. For institutional investors and financial entities, this call opens positions in Spanish sovereign debt across a range of maturities from three to twenty years.

What does this regulation establish?

The resolution convenes the auction of four specific references of State Bonds. All of them expand existing issues, so they are managed as a single issue from their circulation date. Below is the complete detail of each reference:

Key operational aspects established by the resolution:

• Second rounds exclusive to Market Makers: after the ordinary auction, Market Makers have exclusive access to a second round awarded at the marginal price resulting from the main auction.
• Segregable bonds: all references have the classification of segregable bonds (STRIPS), which allows separating coupons from principal for independent trading.
• Restriction on 10-year references: the two references maturing in 2036 require express authorization to perform segregation operations, unlike the 3 and 20-year references.
• Trading market: the securities will be admitted to trading on AIAF Fixed Income Market.
• Expansion of existing references: no new issues are created from scratch; existing references in circulation are expanded, which guarantees liquidity in the secondary market.

Economic and operational impact

This auction has direct implications for fixed income portfolio management and treasury planning of participating entities:

• Maturity diversification: the coexistence of 3, 10 and 20-year references allows institutional investors to build or adjust the duration curve of their portfolios in a single operation.
• Inflation hedge: the reference indexed to Eurozone CPI (1.15%, November 2036 maturity) offers real protection against high inflation scenarios, relevant for pension funds and insurers with long-term liabilities.
• Term premium in the long tranche: the 2.90% coupon at 20 years (October 2046 maturity) reflects the premium required by the market to commit capital for two decades, with implications for portfolio valuation at fair value.
• Competitive advantage for Market Makers: exclusive access to second rounds at the marginal price represents an acquisition opportunity at known conditions and without additional competition, improving the average acquisition cost.
• Guaranteed liquidity on AIAF: admission to trading on AIAF Fixed Income Market ensures an active secondary market for all awarded references.

Who does it affect?

• Market Makers in Spanish public debt: they are the only ones with access to second rounds at the marginal price; they must plan their participation in both phases.
• Institutional investors: investment funds, pension funds, insurers and asset managers operating in Spanish sovereign debt auctions.
• Financial entities (banks and savings banks): with fixed income portfolios or acting as intermediaries in public debt placement.
• Corporate treasuries of large companies: that use State Bonds as a reserve asset or collateral in financing operations.
• Portfolio managers with sovereign fixed income mandates: especially those with duration restrictions or risk-free asset requirements.
• Entities with exposure to European inflation: interested in the reference indexed to Eurozone CPI maturing November 2036.

Practical example

A pension fund with the need to cover long-term liabilities and a sovereign fixed income mandate analyzes the four references available in the October 1, 2026 auction:

• For the short tranche, it opts for the reference at 1.45% maturing April 2029, suitable for three-year liquidity reserves.
• To cover nominal medium-term liabilities, it incorporates the reference at 3.40% maturing October 2036, the highest coupon of the auction.
• To protect part of the portfolio against European inflation, it allocates a portion to the reference indexed at 1.15% maturing November 2036. If Eurozone CPI rises, the principal and coupons adjust upward, preserving real purchasing power.
• If the fund is a Market Maker, it can access the second round of any of these references at the marginal price resulting from the auction, improving its acquisition cost without additional competition.
• For the long tranche, the reference at 2.90% maturing October 2046 fits with very long-duration liabilities, although it implies greater sensitivity to interest rate changes.

What should companies do now?

1. Verify Market Maker status: if your entity has this condition, confirm internal procedures to participate in the second round at the marginal price on October 1, 2026.
2. Review auction participation limits: check that planned positions comply with operational and counterparty risk limits established internally.
3. Evaluate the inflation-indexed reference: analyze whether the 1.15% obligation indexed to Eurozone CPI (November 2036 maturity) fits with the investment policy and inflation hedging mandates of the portfolio.
4. Consult authorization for segregation on 10-year references: if STRIPS operations are planned on references maturing 2036, obtain the express authorization required before executing any segregation operation.
5. Confirm the operational calendar: the auction is on October 1, 2026 and circulation on October 6; adjust settlement and accounting systems to these dates.
6. Update the securities register on AIAF: ensure that internal systems are prepared for the admission to trading of the four references on AIAF Fixed Income Market from October 6.

Official source

Consult complete regulation at official source

Disclaimer: This article is for informational purposes only and does not constitute legal advice. For specific decisions, consult a qualified professional. Source: https://www.boe.es/diario_boe/txt.php?id=BOE-A-2026-20145