The European Central Bank has thrown its full weight behind plans to strengthen the European Securities and Markets Authority, stepping into one of Brussels’ most sensitive financial power battles as the EU pushes for deeper capital markets integration. In an opinion published on 9 April 2026, the ECB backed the European Commission’s reform package and explicitly endorsed giving Esma stronger governance, more resources and broader supervisory powers for Esma.

The opinion is politically significant because it aligns Frankfurt with efforts to move supervision of some of the bloc’s biggest cross-border market actors away from national authorities and closer to the European level. The ECB argued that more integrated capital markets would improve private risk-sharing, reduce fragmentation and support the transmission of monetary policy across the euro area.

Stronger EU supervision

The ECB endorsed direct Esma supervision of major cross-border players and backed a tougher framework for crypto-asset service providers, trading venues, central counterparties and central securities depositories. It also supported stronger investigation, sanctioning and enforcement powers for the Paris-based watchdog.

That stance puts the ECB firmly behind the Commission’s broader effort to reduce national differences in supervision and remove barriers to cross-border capital flows. The opinion also welcomed measures aimed at greater supervisory convergence and easier cross-border activity in asset management, trading and post-trade services.

What it means for Luxembourg

For Luxembourg, the ECB’s intervention lands in the middle of an argument the country has already made publicly. Claude Marx, director general of the CSSF, has rejected the idea that the single market is suffering because key actors are not supervised centrally, arguing there is “no evidence” that the lack of central supervision is hurting its functioning. Instead, he has maintained that Esma is already delivering real convergence through the single rule book, peer reviews, common supervisory actions and other coordination tools, without the need to build what he described as a “big European SEC”.

That view is echoed by the government. Finance minister Gilles Roth has backed stronger supervision, convergence and high standards, but warned that “centralised supervision at EU level will not unlock the capital Europe needs”. Luxembourg’s argument is that Brussels should focus on removing barriers and improving how the single market works in practice, while avoiding unnecessary complexity, bureaucracy and costs.

Against that backdrop, the ECB opinion is politically awkward for Luxembourg. Frankfurt has effectively lined up with those who see a stronger transfer of supervisory authority to the European level as part of the price of a more efficient and integrated capital market. Luxembourg, by contrast, argues that the real priorities remain simplification, burden reduction and practical reforms that improve cross-border activity, rather than shifting more power from national regulators to Paris.

The political pivot, however, is easier to understand. A centralisation drive under capital market integration and the Savings and Investments Union is easier to advocate because there is broader alignment among member states than on the unfinished Banking Union agenda or on wider insurance reform. That is despite the fact that, in the context of banking union, the European Commission has concluded that up to €10trn from household savings could be mobilised towards capital markets, rejuvenating innovation and growth. Still, expanding Esma’s powers is taking precedence, largely because it appears politically easier to advance.

All said and done, Luxembourg’s view remains valid: neither Brussels nor Frankfurt has yet produced evidence that centralising more power in Esma would, by itself, make Europe’s markets deeper, faster or more effective. For now, whichever side of the aisle one sits on, the risk is that Europe centralises authority more quickly than it fixes fragmentation.