Treasury Bills April 2026: interest rates and auction data

Key data

The interest rates resulting from the Treasury Bills auction of April 17, 2026 are now the official reference for the Spanish money market. The Resolution of April 16, 2026 from the General Directorate of Treasury and Financial Policy, published in the Official Gazette on April 25, 2026, makes public the results of the three and nine-month issues: marginal rate, weighted average rate, requested volume and awarded volume.

These data are not merely an administrative formality. For any company, fund or investor with short-term fixed income treasury or products referenced to the Spanish money market, the rates from each auction determine the actual profitability of their positions and the opportunity cost against other alternatives.

What does this regulation establish?

The resolution publishes the official results of the Treasury Bills auction corresponding to the issue of April 17, 2026. Treasury Bills are short-term fixed income instruments issued by the Spanish State, considered low-risk, and constitute the main mechanism for short-term Treasury financing in public debt markets.

The data published in each resolution of this type include:

• Marginal interest rate: the maximum rate at which debt is awarded in the auction. Bids above this rate are excluded.
• Weighted average interest rate: the average of all accepted rates, weighted by the volume awarded at each rate.
• Requested volume: the total of bids received from auction participants.
• Awarded volume: the amount effectively placed by the Treasury among investors.

This auction covers two differentiated terms:

The resulting rates serve as a reference for the Spanish money market and may influence financial products linked to short-term interest rates, such as structured deposits, corporate notes or money market investment funds.

Economic and operational impact

The impact of this auction occurs at three levels:

For institutional investors and financial entities: the awarded rates determine the profitability of short-term public debt positions and condition asset allocation decisions in conservative portfolios. The difference between requested and awarded volume reflects the level of market demand and the Treasury's placement policy.

For individual savers: Treasury Bills rates are a direct reference for profitability for those investing in public debt through the Bank of Spain or intermediaries. In an environment of variable rates, each auction updates the profitability available to the conservative saver.

For companies with referenced financial products: any financial instrument linked to Spanish money market rates may be affected by the evolution of Treasury Bills rates. This includes everything from bank deposits to short-term financing structures.

Who does it affect?

• Institutional investors (investment funds, insurance companies, pension funds) with positions in Spanish public debt at short term.
• Financial entities that participate directly in Treasury auctions or use the resulting rates as internal reference.
• Companies with treasury surpluses invested in Treasury Bills or in money market funds referenced to the Spanish market.
• Individual savers who invest directly in Treasury Bills through the Bank of Spain or their financial entity.
• Asset managers and financial advisors who must update reference profitability for their conservative portfolios.
• CFOs and financial directors of companies managing corporate treasury with short-term fixed income instruments.

Practical example

A medium-sized company with 2 million euros of treasury surplus decides to invest in 3-month Treasury Bills as a conservative alternative to a bank deposit. To make that decision, the financial director consults the results of the April 17, 2026 auction: the weighted average rate awarded indicates the actual profitability they will obtain if they participate in the next auction or if they acquire Bills in the secondary market at that reference price.

If the weighted average rate of the 3-month auction results, for example, higher than the rate offered by their bank in an equivalent term deposit, the decision to invest in Treasury Bills has direct quantitative support. Similarly, if the requested volume far exceeds the awarded volume, the financial director knows that demand is high and that auction access may be competitive, then evaluating the secondary market as an alternative.

This analysis, which previously required accessing dispersed sources, is now centralized in the resolution published in the Official Gazette with reference BOE-A-2026-9073.

What should companies do now?

1. Consult the awarded rates in the official resolution (BOE-A-2026-9073) to know the marginal and weighted average rates of the 3 and 9-month issues from April 17, 2026.
2. Compare the resulting rates with available short-term investment alternatives (deposits, money market funds, notes) to optimize treasury management.
3. Review own financial products referenced to Spanish money market rates to anticipate possible variations in their profitability or cost.
4. Update treasury projections if the company has positions in Treasury Bills or instruments linked to these rates, incorporating the new reference data.
5. Follow the Treasury auction calendar to plan in advance investment decisions in short-term public debt.