ECB reserve debate returns to banks

The European Central Bank is considering whether to double the proportion of cash that eurozone lenders must hold in unremunerated reserve accounts, reviving a sensitive policy question with direct consequences for bank liquidity, profitability, and central bank finances.

The proposal under discussion would raise minimum reserve requirements to 2% from 1% of banks’ customer deposits and some other funding sources. The change is still at an early stage and has not yet been formally discussed by the ECB’s Governing Council, with a decision expected by autumn.

A higher requirement would reduce the amount of interest paid by the Eurosystem on excess liquidity held by banks. The ECB and the 21 national central banks of the euro area are paying a 2.25% interest rate on about €2.16 trillion of excess liquidity, creating annual outlays of approximately €48.7 billion. Doubling mandatory reserves, which are not remunerated, from €173.56 billion would reduce the combined annual interest bill by nearly €4 billion.

The current reserve requirement was cut from 2% to 1% during the eurozone debt crisis in 2012. In 2023, the ECB set the remuneration of minimum reserves at 0%, saying the change would preserve the effectiveness of monetary policy while improving its efficiency by reducing the amount of interest paid on reserves.

Central bank losses have become more politically exposed after years of bond-buying stimulus, which left the Eurosystem with a very large balance sheet and abundant banking-sector liquidity. As policy rates rose to contain inflation, central banks began paying much more interest on commercial bank deposits, while assets bought during the low-rate period generated lower returns.

Profit is not the ECB’s formal objective. Its mandate is price stability, and monetary decisions are judged against inflation rather than earnings. Even so, sustained losses can create institutional and political strain. Loss-making national central banks may have less capacity to pay dividends to governments, and in more difficult cases may face questions about capital support from the state. Those pressures are especially visible in cash-rich economies where central bank outlays have become easier to quantify.

The reserve debate sits within the ECB’s wider reassessment of how monetary policy is implemented as eurozone banking liquidity gradually normalises. Christine Lagarde’s recent remarks on eurozone resilience and policy room kept attention on inflation, refinancing costs, and the path of interest rates. Minimum reserves add a balance sheet dimension to the same environment, shifting attention from headline rates to the mechanics through which policy is transmitted.

For banks, a higher unremunerated reserve requirement would act as an earnings drag rather than a conventional capital shock. Mandatory reserves do not disappear from the balance sheet, but the absence of remuneration changes the economics of holding them. Lenders would place more cash at the central bank without earning interest on that portion, at a time when interest margins, deposit pricing, and liquidity management are already under scrutiny.

Many European banks are stronger than they were during earlier phases of eurozone stress. Higher rates have lifted net interest income across the sector, and capital and liquidity positions have generally remained robust. That strengthens the argument among some policymakers that lenders can absorb a higher reserve requirement without destabilising credit supply.

The cost would not fall evenly. Banks with large deposit bases and stronger liquidity positions may carry a larger absolute burden, while smaller or more funding-sensitive lenders will examine whether the change affects liquidity buffers, money-market activity, and pricing decisions. Treasury teams will also revisit the relative value of deposits, wholesale funding, collateral management, and central bank balances if more reserves earn no return.

The debate comes as the ECB’s operational framework review approaches. The central bank has said it will continue steering monetary policy through the deposit facility rate, while reviewing key parameters in 2026 as excess liquidity declines. Raising reserve requirements would not replace that framework, but it would change the quantity of unremunerated reserves inside it and accelerate the gradual retreat from the extreme liquidity conditions created after the financial crisis, eurozone debt crisis, pandemic, and energy shock.

Companies outside banking would feel any effect indirectly through the cost and availability of credit. Bank profitability influences lending appetite, deposit pricing, credit spreads, and the willingness of lenders to absorb risk. A modest reserve change may not materially alter loan availability on its own, but it would add another factor to bank funding models at a time when businesses are already dealing with higher debt-servicing costs, more selective credit conditions, and uncertainty over the future path of eurozone rates.

The proposal also illustrates how decisions made during the long low-rate period continue to shape today’s financial system. Asset purchases, excess liquidity, deposit facility rates, and minimum reserves now interact in ways that affect central bank accounts, commercial bank earnings, government expectations, and the politics of monetary normalisation.

A return to 2% would be technical in form, but the distribution of cost would be clear. Central banks would lower part of their interest expense, while commercial banks would lose remuneration on a larger slice of their liquidity. Some of that pressure could eventually appear in deposit pricing, lending margins, or balance sheet strategy.

The autumn decision will indicate how far the ECB is willing to adjust the plumbing of eurozone monetary policy while rates remain central to inflation control. After several years in which the headline policy rate dominated the discussion, reserve requirements are bringing attention back to the quieter mechanics of central banking — and to the question of who absorbs the cost of a system still carrying the legacy of past stimulus.