The invisible stress test

This article is part of In conversation about sustainable finance & emission reduction systems, a new series by Diego Balverde. You're reading volume eight of the Collateral Crisis series. Here is volume seven

Prologue

Europe's banks are no longer being tested only in official exercises, supervisory templates or modelled scenarios.

They are being stress-tested every day by the price of electricity, the cost of refinancing, the fragility of freight corridors, the repricing of sovereign debt, the weakening of industrial cash flow and the progressive incorporation of climate risk into collateral and supervision.

That is what makes this phase different.

The official numbers still look solid enough to calm the surface: EU and EEA banks reported a CET1 ratio of 16.3%, an LCR of 160.7%, an NSFR of 126.8%, total assets of €29.1 trillion, an NPL ratio of 1.8% and a return on equity of 10.7% in the third quarter of 2025. But a balance sheet can look stable while the system underneath it is becoming less stable by the month.

That is the invisible stress test. The one that does not wait for a supervisor to publish a scenario because reality is already running it every day.

The test begins with energy, not with banks

A bank does not need to be badly managed to come under pressure. It only needs to be connected to an economy whose operating costs have become structurally more volatile. In Europe, that begins with energy.

Industrial borrowers do not live inside spreadsheets. They live inside gas prices, electricity prices, transport rates and production cycles. When power remains expensive and uncertain, industrial planning weakens. When industrial planning weakens, margins compress. When margins compress, debt-service capacity deteriorates. And when debt-service capacity deteriorates, the bank is already inside the stress test whether it wants to be or not.

The ECB itself has stated that in the first quarter of 2026 banks expected to tighten credit standards across all major loan categories, explicitly citing geopolitical tensions, energy developments and higher funding costs. That means energy is no longer a sector issue. It has become a banking transmission channel. The stress test is already happening at the borrower level before it ever appears at the supervisory level.

This is why apparently comfortable banking ratios can be misleading if read in isolation. A borrower can remain current on payments while already becoming less financeable. The deterioration does not start with default. It starts with weaker coverage, tighter refinancing conditions, reduced investment and greater vulnerability to the next shock.

That is exactly what makes the current phase dangerous. Banks are not primarily being tested by yesterday's losses. They are being tested by tomorrow's weakening cash flows. A system with Stage 2 loans still at 9.3% is not a system in panic, but it is clearly a system already carrying a large volume of assets under reinforced surveillance. That is invisible stress in practice. Not collapse, but widespread latent deterioration.

The second test is refinancing under harder conditions

The next daily stress test comes from refinancing. During the years of ultra-low rates, a large part of the corporate and sovereign system learned to live with cheap rollover. That world is gone. Even if policy rates eventually normalize further, the financial system is not returning to the same conditions under which debt was built. Banks are funding themselves in a more expensive environment, deposit competition has become more relevant, wholesale markets are less forgiving and borrowers refinancing now do so in a world of weaker margins and greater uncertainty.

This matters because the banking system does not only carry current loans. It carries the expectation that large parts of the economy will continue to refinance successfully. The invisible stress test is whether that expectation still holds.

The ECB's bank lending survey is clear enough on this point. In the fourth quarter of 2025, euro area banks tightened credit standards for firms by a net 7%, after 4% in the previous quarter, bringing cumulative tightening since the third quarter of 2024 to 19%. For the first quarter of 2026 they expected a further 6% tightening. This is not the behavior of a system that feels comfortable with the refinancing outlook. It is the behavior of a system already anticipating greater difficulty in preserving credit quality.

And when credit standards tighten before a visible default wave appears, that is not calm. That is pre-emptive defense. The system is already treating refinancing itself as a risk event.

This becomes more serious when combined with the EBA's asset-quality composition. Consumer credit NPLs were already at 5.4%, SME loans at 4.6%, and gross inflows into default approached €110 billion in the first half of 2025. Those numbers do not signal systemic collapse, but they do show that weaker segments are already under pressure. Once those pressures interact with refinancing waves at higher rates and under tighter standards, the test stops being hypothetical. It becomes mechanical.

Some borrowers will pass by paying more. Some will pass by shrinking. Some will fail quietly through tighter terms, lower available credit and deteriorating collateral value. That is what an invisible stress test looks like in the real economy.

The third test is sovereign risk coming back through the side door

Europe's banking system never truly stops being exposed to sovereign risk because sovereign debt remains central to liquidity, regulation and portfolio structure. What changes over time is how dangerous that exposure becomes.

In 2025, the ECB explicitly warned that sovereign vulnerabilities in the euro area stemmed from still elevated debt levels in some countries, rising issuance needs and changing investor demand, while the Eurosystem's reduced footprint in bond markets contributed to steeper yield curves. That sentence matters because it means the public sector side of the balance sheet is no longer a neutral backdrop. Governments need more financing, markets are more price-sensitive and debt must be absorbed under less generous central-bank conditions.

Banks therefore face a second layer of daily testing: not only whether private borrowers remain stable, but whether sovereign-market conditions remain calm enough to avoid feeding stress back into funding and valuation. This does not automatically mean a return to the old sovereign-bank doom loop in its most dramatic form. But it does mean that the separation between public debt pressure and bank balance-sheet pressure is getting thinner again. If states issue more, if growth slows, if private borrowers weaken and if collateral becomes more sensitive to climate and transition risk, the same banking system absorbs stress from multiple directions.

This is exactly why the official 2025 EU-wide stress test remains important. Under the adverse scenario, aggregate CET1 depletion was 370 basis points, bringing the ratio down to around 12.1%. That is not a collapse. But it is a reminder that resilience still depends on the starting point being strong. It does not mean the system is immune to overlapping shocks. It means the system survives them better than before if they remain inside the tested range. The invisible stress test asks a harsher question: what if daily reality becomes more persistent than the official scenario?

The fourth test is climate risk moving into operations and collateral

The final layer of this invisible stress test is climate and transition risk becoming operational rather than rhetorical. For years, climate risk could be discussed as disclosure, governance or long-term alignment. That is no longer enough.

In 2025, the ECB decided to introduce a climate factor into the Eurosystem collateral framework in order to protect itself against declines in collateral value under adverse transition shocks, with application to marketable assets issued by non-financial corporations from the second half of 2026. In January 2026, the ECB also stated that climate and nature-related risks had been embedded more deeply into day-to-day processes and into the policy framework. That means the stress test is no longer confined to voluntary narratives. It is moving into monetary operations, collateral treatment and macro-financial assessment.

Once climate risk enters collateral, it stops being abstract for banks. It becomes valuation, haircut, eligibility and liquidity. This changes how banks should read industrial assets, commercial buildings, logistics platforms, ports and any operating system dependent on cheap energy, low friction and a weak carbon penalty. The question is no longer only whether an asset still has value today. The question is whether the market and the monetary system will continue to trust that asset to support debt tomorrow. That is a much harder standard.

And once that standard shifts, the stress test becomes daily because every borrower linked to older operating assumptions is effectively being re-evaluated in real time. Banks are no longer waiting for climate risk to emerge. They are being forced to integrate it while still managing energy volatility, sovereign pressure and refinancing risk. That is why the stress test is invisible only to those still looking at the old indicators alone.

Implementation and value capture

If Europe's banking system is being stress-tested every day by reality, then the only meaningful response is to reduce risk where reality creates it. That means lowering energy waste, reducing logistics friction, shortening idle time, stabilizing operating costs and making cash flow more predictable. This is where operational discipline becomes financial defense.

If an industrial or logistics operation cuts energy use by 15%, reduces idle time by 20% and lowers logistics costs per ton by 10% to 15%, the effect is not only operational. It improves cash-flow quality. Better cash-flow quality improves credit quality. Better credit quality can reduce financing spreads by 50 to 150 basis points. On a €100 million debt structure, that means €500,000 to €1.5 million per year. That is not marginal. That is a strategic response to the daily stress test.

This is where BalGreen becomes practical rather than symbolic. It provides a framework to identify where money is leaking through energy, delay, inefficiency and process disorder, and how those losses can be converted into measurable savings, stronger cash flow and better financeability. A port that reduces energy intensity, waiting time and coordination failures is not just becoming greener. It is becoming more defensible to lenders. A company that documents lower volatility and lower waste is not simply improving operations. It is changing how the banking system prices its survival. In an environment where banks are tested every day by the fragility of the economy, the borrower who can prove lower friction becomes part of the banking solution, not part of the banking problem.

Analysis

The real debate is no longer whether Europe's banks can pass a formal stress test. They probably can, at least under the assumptions already modelled. The real debate is whether they can pass the informal one that is already running every day.

How much of current banking strength still depends on a delayed recognition of deterioration rather than on genuine improvement in borrower quality? How many firms are still performing only because they have not yet had to refinance under the full new cost structure? How many balance sheets still look solid because sovereign pressure, industrial weakness, freight instability and climate repricing have not yet converged with maximum force?

Can a system still call itself resilient if a meaningful part of that resilience depends on the assumption that shocks will not overlap too long? What happens if official stress tests remain bounded while real-world frictions become chronic?

And perhaps the hardest question of all: are banks still financing productive expansion, or are they increasingly financing only what looks least likely to go wrong in a structurally more expensive Europe? Because if the answer is the second, then the invisible stress test is already changing the nature of the banking system. Credit stops being a neutral growth mechanism and becomes a defensive allocation mechanism. At that point, the issue is no longer just whether banks are strong. It is whether the economy remains financeable enough to keep banks looking strong.

Conclusion

My conclusion is direct. The invisible stress test is already underway. It is being run by energy markets, by war, by sovereign funding needs, by refinancing pressure, by climate-related collateral adjustments and by the weakening stability of industrial cash flow. Banks may still report comfortable ratios, but the system that supports those ratios is under more daily pressure than the surface numbers admit. That is the real message of this stage.

Europe's banking future will therefore not be defined only by capital buffers, liquidity ratios or supervisory compliance. It will be defined by whether the economy those banks finance can become less fragile, less energy-wasteful, less logistically inefficient and more credible under stress. Whoever can reduce friction, stabilize cash flow and defend collateral will remain financeable. Whoever cannot will increasingly discover that the stress test was never waiting for the supervisor. Reality had already started it.

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