Official euro exchange rates for March 25, 2026: what companies need to review

Key data

Companies operating with foreign currencies have a specific accounting and legal obligation: to use the official exchange rates published daily by the Banco de España as a reference for their conversions. The Resolution of March 25, 2026 of the Banco de España publishes the euro exchange rates corresponding to that date, established by the European Central Bank, with full legal validity from March 25 itself.

This is not an optional or indicative publication. Article 36 of Ley 46/1998, of December 17, on the Introduction of the Euro, establishes that these rates have the status of official exchange rates. Using them correctly is not a best practice: it is an obligation with direct accounting and tax consequences.

What does this regulation establish?

The Banco de España acts as the official publication channel in Spain for the exchange rates set daily by the European Central Bank. Each business day, a resolution is published with the euro exchange rates against the main world currencies, which acquire official status at the time of their publication.

The legal framework underpinning this publication is Article 36 of Ley 46/1998, which regulates the introduction of the euro and establishes the official reference mechanism for currency conversions. These rates are the ones that must be applied in:

• Currency conversions in domestic and international commercial transactions.
• Accounting valuation of assets and liabilities denominated in foreign currency.
• Recording of foreign currency transactions in company accounts.
• International contracts requiring a legal exchange rate reference.
• Imports and exports settled in currencies other than the euro.

Publication in the BOE the following day (March 26, 2026) is the formal dissemination mechanism, but the rates are effective from March 25, 2026 itself, the date to which they correspond.

Economic and operational impact

The impact of these exchange rates is not abstract. Every company that closes a transaction in dollars, pounds, yen or any other currency on a specific date must record that transaction at the official rate for that day. A deviation from the official rate can generate valuation differences that directly affect the accounting result and the taxable base.

The most relevant operational effects for companies are:

• Valuation of invoices in foreign currency: invoices issued or received on March 25, 2026 in foreign currency must be converted at the official rate published for that date.
• Accounting close of transactions: any pending transaction that is settled on that date takes this official rate as its reference.
• Exchange differences: if the rate applied at the time of collection or payment differs from the initial recording rate, an exchange difference is generated that must be correctly accounted for.
• Contracts with official exchange rate clauses: contracts that explicitly reference the official ECB or Banco de España rate are bound to this value for settlements on March 25, 2026.

For companies with a high volume of international transactions, the correct application of the official rate for each day is an accounting and tax compliance requirement that must be automated in their ERP or financial management systems.

Who is affected?

• Exporting and importing companies that invoice or receive invoices in currencies other than the euro.
• Companies with international subsidiaries or suppliers that consolidate accounts in foreign currency.
• Self-employed individuals with clients or suppliers outside the euro zone who issue or receive invoices in foreign currencies.
• CFOs and financial directors responsible for accounting close and the valuation of foreign currency positions.
• Tax and accounting advisors who manage the accounts of companies with international operations.
• Companies with international contracts that include clauses referencing the official ECB exchange rate.
• Financial and credit institutions that operate with foreign currencies and must record their positions at the official rate.

Practical example

A Spanish e-commerce company sells products to customers in the United States and receives payment in dollars. On March 25, 2026, it receives a payment of 10,000 USD corresponding to a sale made a few days earlier.

To record that payment in its accounts, it must convert the 10,000 USD to euros by applying the official exchange rate published by the Banco de España for March 25, 2026, which is the one covered by this resolution. If the official exchange rate for that day were, for example, 1.08 USD per euro, the accounting income would be 9,259.26 euros.

If the sale was initially recorded at a different rate (for example, the rate on the day the invoice was issued), the difference between the two rates generates an exchange difference that must be recorded as financial income or expense. Using a rate other than the official one for recording the payment would be an accounting error with potential tax implications.

This same principle applies to payments to foreign suppliers, settlement of loans in foreign currency or any other non-euro currency transaction closed on March 25, 2026.

What should companies do now?

1. Verify the official rate for March 25, 2026 in the resolution published in the BOE (BOE-A-2026-7031) or on the Banco de España website, and apply it to all foreign currency transactions closed on that date.
2. Review foreign currency transactions recorded on that day to confirm that the rate applied in the accounting system matches the published official rate. Any deviation must be corrected.
3. Calculate and record exchange differences that may arise between the initial recording rate of a transaction and the official rate on the day of its settlement or collection.
4. Automate the loading of official rates into the ERP or financial management system if not yet configured, to avoid manual errors in recording foreign currency transactions.
5. Inform the administration and accounting team of the obligation to use the official ECB rate published by the Banco de España as the legal reference, especially at month-end or quarter-end closes.

Official source

Disclaimer: This article is for informational purposes only and does not constitute legal advice. For specific decisions, please consult a qualified professional. Source: https://www.boe.es/diario_boe/txt.php?id=BOE-A-2026-7031