What it is

The Banking Union is not a single legal act but an institutional architecture that moves core responsibilities for banks in participating Member States from the national to the European level. It was launched in response to the financial and sovereign-debt crises, when the tight link between banks and their home governments — the "doom loop" — showed that national supervision and national bailouts could destabilise whole states. The Banking Union answers that by centralising supervision and resolution, so that decisions about the largest banks are taken by European bodies against common rules.

It is conventionally described as resting on three pillars. Two are in force. The first is the Single Supervisory Mechanism, under which the European Central Bank directly supervises the significant banks of participating countries and oversees the rest through national competent authorities. The second is the Single Resolution Mechanism, under which the Single Resolution Board plans for and, where necessary, executes the resolution of failing banks, financed by the Single Resolution Fund. The third pillar, a European Deposit Insurance Scheme, remains a proposal and is not in force; deposit protection is still provided by national deposit guarantee schemes.

How the pillars connect to resolution

The Banking Union's resolution pillar is what removes the expectation of taxpayer bailouts. The Single Resolution Mechanism applies the same resolution toolkit as the wider EU framework — including bail-in, the sale-of-business tool and bridge institutions — but does so through a European authority for banks under its remit. Supervision and resolution are deliberately separated: the supervisor judges whether a bank is failing or likely to fail, while the resolution authority decides whether resolution is in the public interest and how to carry it out. This division of labour, matched by the division between competent authorities and resolution authorities, is central to the credibility of the framework.

Deposit insurance is the missing link. Because there is as yet no common scheme, a depositor's protection still depends on the national scheme of the bank's home country, which can leave confidence unevenly distributed across the union. Completing the third pillar has been debated since 2015 without agreement.

The Banking Union has no founding treaty article of its own; it is built from separate instruments. The Single Supervisory Mechanism rests on the SSM Regulation, Council Regulation (EU) 1024/2013. The Single Resolution Mechanism rests on the SRMR, Regulation (EU) 806/2014, which mirrors the substantive rules of the Bank Recovery and Resolution Directive for participating states. Deposit protection remains governed by the Deposit Guarantee Schemes Directive, Directive 2014/49/EU, pending any adoption of a common scheme. This entry therefore describes a composite rather than a single codified regime.

Practical relevance for banks and investors

For banks, membership of the Banking Union determines who supervises them and who would resolve them: the ECB and the Single Resolution Board for significant institutions, national authorities for the rest. For investors, it shapes where loss-absorbing capacity sits and how predictably resolution rules would be applied across borders. The incompleteness of the deposit pillar is a standing feature of any assessment of the union's resilience.