The euro handles about one-fifth of the world's financial business. Not spectacular, perhaps, until you consider that it competes with a currency - the US dollar - that was already dominant before the euro even existed, and that the dollar still handles roughly 57% of global foreign exchange reserves, according to IMF data. One-fifth is not nothing.

Today, the European Central Bank published its 25th annual review of the euro's international role, and the headline number is roughly 20% - up modestly from the year before. But the story is not really about one-fifth. It is about a record-breaking surge in euro-denominated debt issuance, a first-ever victory in the green bond market, and a candid warning from ECB President Christine Lagarde that an unusual window of opportunity is open right now - and that European governments could easily waste it.

The Background

To understand why this matters, start with what a reserve currency actually is. When central banks - the official money managers of governments around the world - hold savings, they mostly hold them in foreign currencies rather than gold or anything else. The currency they hold most of is the dollar, which has sat at the top of this pile since the end of World War II. The euro, introduced in 1999, is the distant second.

Why does it matter which currency holds this status? Because countries that issue a globally trusted currency get to borrow cheaply. Demand for their government bonds - the financial instruments that governments sell to raise money, essentially IOUs that pay interest - stays high, which keeps their interest rates low. Their banks can lend across borders more easily. Their companies can issue debt in their home currency without paying an exchange-rate premium. It is structural competitive advantage built into the plumbing of global finance.

For most of its 27-year life, the euro has hovered between 19% and 25% of global reserve use, depending on how you measure it and when. Its composite index - a measure the ECB calculates by averaging the euro's share across six different indicators, from reserve holdings to global settlements to exchange-rate regimes - sat around 20% in 2025. That is a gradual rise since Russia's invasion of Crimea in 2014, which first prompted central banks outside Europe to ask whether holding all their reserves in dollars was wise.

The dollar's share, by contrast, has been falling - though "falling" is a relative term. According to the Atlantic Council, the dollar's portion of global reserves declined from 71% in 1999 to around 56.3% by end-2025. But most of what the dollar lost did not flow to the euro. It went to smaller, non-traditional currencies - the Australian dollar, the Canadian dollar, and to a lesser extent China's renminbi. The euro has held roughly steady, which is why today's numbers showing modest growth are actually something to notice.

What Is Actually Happening

The headline of the ECB's June 2026 report is a 20% composite share - but the more interesting number is 30%. That is how much euro-denominated international debt issuance grew in 2025 compared to 2024, reaching the highest level since the single currency launched. International debt means bonds and loans issued by borrowers outside the eurozone, in euros - a sign that companies and governments worldwide chose the euro as their preferred funding currency at a record rate.

And one category within that pile is genuinely historic. For the first time, the euro became the leading currency in the global green and sustainable bond market, surpassing the dollar. Green bonds are debt instruments that require proceeds to be spent on qualifying environmental projects. The euro-denominated slice of this market reached nearly $100 billion, according to the ECB's full report. That is a meaningful benchmark given how quickly sustainable debt has grown: the cumulative global market for labeled sustainable bonds crossed $6.1 trillion by early 2025, according to World Bank data.

The euro won that race partly because the US retreated from it. Several major US financial institutions scaled back commitments to net-zero investing alliances in late 2024 and 2025, making dollar-denominated sustainable debt less attractive to international buyers focused on climate credentials. Europe, by contrast, deepened its regulatory framework - the European Green Bond standard gained full traction in early 2025, requiring proceeds to align with the EU's strict taxonomy of what counts as genuinely green.

Foreign money also flowed into eurozone assets at rates close to historical highs. Portfolio inflows - investments by foreign investors in eurozone stocks and bonds - approached records, reflecting a degree of global confidence in European financial stability at a moment when US policy unpredictability was generating anxiety in markets.

Yet the ECB is careful to frame all of this as a window, not a victory. "There is an opening for the euro to enhance its global appeal - provided that European policymakers create the necessary conditions and put words into action," Lagarde said. She listed three pillars that must be reinforced: economic resilience, legal and institutional integrity, and geopolitical credibility. None of them are guaranteed.

The Money Trail

Follow the money and you find that the euro's gains are real but built on fragile ground.

The biggest structural problem is that the eurozone still does not have a single, deep, liquid capital market. Think of it this way: when global investors want to hold dollar assets, they buy US Treasury bonds - one unified, enormous, highly liquid market where they know they can always find a buyer if they need to sell. The eurozone equivalent is 20 different sovereign bond markets, in 20 countries, with 20 different credit ratings, 20 different legal systems, and no single pooled EU debt instrument of comparable scale.

This is not a new problem. But the ECB is now explicitly saying it must be solved before the euro can genuinely challenge the dollar. The report calls for completing the EU's Savings and Investment Union - the policy project launched in March 2025 as the successor to the old Capital Markets Union - under an ambitious timetable. The SIU aims to connect approximately €10 trillion in European household savings currently sitting in low-yield bank deposits to productive capital market investments, according to the EU Council. The Draghi report, which mapped Europe's competitiveness gap, estimated the EU needs an additional €750-800 billion a year in investment by 2030 just to keep pace.

The ECB also explicitly calls for joint EU public debt - common bonds issued collectively by EU member states, not individually by each one. That remains politically explosive in northern Europe, particularly in Germany and the Netherlands, where the idea of German taxpayers backing Italian debt is deeply unpopular. Without it, the euro lacks the single safe-haven asset that makes reserve currencies sticky.

Central banks worldwide are simultaneously signalling distrust of the existing system. They have been buying gold at an accelerated pace - Poland, China, India, and Türkiye have added hundreds of tonnes between them since 2022, according to the ECB report. Historically, large gold purchases are how central banks hedge against currency risk without making a public statement about which currency they distrust. It is a vote cast in silence.

Meanwhile, several countries are building alternative payment infrastructure. Digital-currency settlement networks, blockchain-based cross-border payment systems, and bilateral swap agreements between central banks are all advancing. These are not yet threatening to the dollar or the euro in terms of volume. But they represent a parallel plumbing system being built underneath the existing one - and whoever's currency runs through it when it reaches scale will benefit.

What People Are Doing About It

The ECB's own institutional response has three tracks. It is pressing ahead with the digital euro - a central bank digital currency that would allow the Eurosystem to offer digital payments directly to citizens and businesses, rather than relying on private banks as intermediaries. The project is framed not merely as a payment innovation but as a sovereignty tool: if global digital payments migrate to private platforms or foreign central bank currencies, the euro's day-to-day relevance shrinks.

It is also expanding the EUREP facility - the enhanced repo facility that allows central banks outside the eurozone to borrow euros from the ECB against collateral during market disruptions. This is the ECB's version of a global backstop: a promise to international holders of euro assets that they can always access liquidity in a crisis. That promise, if credible, makes holding euros less risky and therefore more attractive.

On the market integration side, the EU's Savings and Investment Union is moving through its legislative calendar. In December 2025, EU finance ministers agreed on a position to revitalise the EU's securitisation market - the mechanism by which banks package loans into tradeable securities, freeing up capacity to lend more. According to EU Perspectives, securitisation reform is considered the first concrete legislative deliverable under the SIU, and European Commissioner Maria Luís Albuquerque has said the remaining SIU legislation could be agreed within a year, if the political will exists.

International bond issuers are responding to incentives. Euro-denominated issuance grew not just in Europe but in the United States and emerging markets, according to the ECB report - meaning borrowers in those regions actively chose to raise money in euros rather than their own currencies or dollars. For emerging-market governments with large green investment programs to finance, the euro's regulatory clarity in the sustainable debt market is a practical draw.

The Bottom Line

The euro quietly had its best year in a decade in 2025 - record debt issuance, a landmark win in the green bond market, and near-record foreign investment flows. But the ECB's own report reads less like a celebration than a warning. The gains are real and may not last. The structural conditions that would make the euro a true challenger to the dollar - deep integrated capital markets, a shared safe-haven debt instrument, genuine geopolitical weight - remain works in progress after 25 years. The window Lagarde describes is open. Whether European governments are willing to walk through it is a different question entirely.

Timeline

  • January 1999 - The euro is introduced as a common currency across the eurozone.
  • March 2014 - Russia's invasion of Crimea begins a gradual shift in central bank diversification away from dollar concentration.
  • February 2022 - Russia's full-scale invasion of Ukraine accelerates central bank gold purchases globally; the dollar's reserve dominance comes under renewed scrutiny.
  • September 2024 - The Draghi report on EU competitiveness estimates Europe needs €750-800 billion in additional annual investment by 2030.
  • December 2024 - The European Green Bond standard enters full force, requiring proceeds to align with EU taxonomy.
  • March 2025 - The European Commission formally launches the Savings and Investment Union, replacing the Capital Markets Union.
  • December 2025 - EU finance ministers agree a council position on securitisation reform, the first major SIU legislative deliverable.
  • End-2025 - Euro-denominated international debt issuance reaches its highest level since 1999, up 30% year-on-year.
  • End-2025 - The euro overtakes the dollar as the leading currency in the global green and sustainable international bond market for the first time.
  • End-2025 - The dollar's share of global foreign exchange reserves falls to around 56.3%, its lowest since the mid-1990s, according to the Atlantic Council.
  • 2 June 2026 - The ECB publishes its 25th annual review of the euro's international role, showing the composite index rising to around 20%.

Summary

Who - The European Central Bank (ECB), issuer of the euro, and ECB President Christine Lagarde.

What - The ECB's annual review of the euro's international role shows the currency's share of global financial indicators rose to around 20% in 2025, with record euro-denominated debt issuance and the euro overtaking the dollar in the green bond market for the first time. The bank warns that structural reforms - deeper EU capital markets, joint EU debt, progress on a digital euro - are needed to turn modest gains into lasting influence.

When - The 2025 data was published today, 2 June 2026. The trends described run from Russia's annexation of Crimea in 2014 through end-2025.

Where - The eurozone, with global implications for central bank reserve management, international debt markets, and the competitive position of the dollar.

Why - Geopolitical turbulence, US policy unpredictability, and structural demand for climate-aligned debt have created an unusual opening for the euro to expand its global footprint. The ECB argues that European policymakers must now act - on capital market integration, joint financing, and digital payments - or the opportunity will pass.