The systemic risks of financial concentration
For many years, concentration was portrayed almost exclusively as a sign of success. The most efficient companies grow, acquire competitors, and attract capital and talent, while markets reward those that achieve the scale needed to innovate. All of this is true. But beyond a certain point, scale no longer generates efficiency alone; it also creates dependence. When debt, savings, technology, and market power become concentrated in the hands of a few entities and in a limited number of places, a localized problem can spread throughout the entire system. The defining concept of our time, therefore, is not simply growth, but balance. And preserving that balance requires diversity.
Debt concentration: Governments, Corporations, and Banks
Let us begin with public debt. According to the International Monetary Fund’s Fiscal Monitor, global public debt reached nearly 94 percent of GDP in 2025 and, on its current trajectory, could reach 100 percent by 2029 (IMF, 2026). This figure is concerning in itself, but it does not capture the full extent of the risk. The issue is not merely how much debt exists, but where it is concentrated, who must refinance it, and under what conditions. The United States and China, the world’s two largest economies, are also among the countries where debt accumulation is greatest. The IMF projects that gross public debt will reach nearly 142 percent of GDP in the United States and 127 percent in China by 2031 (IMF, 2026).
One might argue that a large economy, particularly one that issues debt in its own currency, enjoys greater room for manoeuvre than a smaller country. This is also true. Yet every maturing security must find a new buyer, and today refinancing generally occurs at higher interest rates than those applied when much of the debt was originally issued. In just four years, the IMF notes, global interest payments have risen from 2 percent to nearly 3 percent of GDP (IMF, 2026). This is not merely an accounting adjustment: it represents resources diverted from investment, education, healthcare, the energy transition, and social protection. Higher interest expenditure also intensifies competition for available savings.
These considerations reveal a first dangerous form of concentration: a growing share of global demand for capital comes from a few enormous sovereign issuers. If they must offer higher yields to place ever-larger volumes of securities, borrowing costs rise for everyone else as well. The IMF notes that supply-driven increases in U.S. yields are transmitted almost entirely to other bond markets. In other words, a decision made in Washington affects the cost of a mortgage in Milan, an industrial plant in Germany, and the debt of an emerging-market economy. Can markets still be considered truly diversified when the pricing of financial assets depends so heavily on a single financial center?
Moreover, debt is not concentrated solely in the public sector: businesses and households are also highly indebted. As long as incomes, revenues, and asset values continue to rise, this accumulation appears manageable. But when a shock occurs—whether inflation, recession, war, falling real estate prices, or a correction in technology markets—all market participants may seek liquidity simultaneously. Governments must refinance their debt and support the economy; businesses must roll over loans and bonds; and households reduce spending to meet higher mortgage payments. What is individually a rational attempt to reduce risk becomes, collectively, a catalyst for crisis. It is the familiar trap of a liquidity run, but within a much larger, more interconnected, and faster-moving system.
For Europe, this vulnerability has an additional dimension: corporate financing remains heavily dependent on the banking system. According to data collected by the European Central Bank at the end of 2025, nearly 80 percent of euro-area non-financial corporate debt takes the form of bank loans, compared with less than 25 percent in the United States. In the United States, by contrast, bond markets play a central role, accounting for more than 75 percent of corporate debt (ECB, 2025a). To be clear, banks have supported Europe’s productive sector for decades, particularly its small and medium-sized enterprises. Yet even when that support is robust, a system standing on one leg remains fragile. European companies’ limited access to debt markets leaves them highly exposed to concentration risk within the banking system.
Consider what might happen if European banks reduced their exposure to businesses because of stricter capital requirements, a deteriorating economic cycle, rising risks, or simply a shift toward more profitable activities. This is not an implausible scenario, given that no European bank consistently ranks among the world’s twenty largest by market capitalization, despite their substantial balance-sheet assets (SIFMA/Bloomberg, 2025). Could the shareholders of these institutions eventually demand changes to their business models to bring returns closer to those generated by their American and Chinese counterparts?
In such a scenario, with European banks withdrawing from lending to businesses and households, a large company could issue bonds, access international investors, or turn to private credit. A medium-sized family-owned business, by contrast, often lacks these options or can pursue them only at prohibitive cost and after lengthy delays. If bank lending contracts and no sufficiently deep alternative market exists, even financially sound companies may fail because of insufficient liquidity. In such cases, default does not necessarily reflect a poor business model, but rather the absence of adequate bridging finance.
In the first quarter of 2026, the ECB reported that the perceived gap between demand for and access to credit remained positive. Its semi-annual survey indicated that this gap had increased to 5 percent. Firms also reported higher interest rates and financing costs, together with stricter collateral requirements (ECB, 2025b).
The consequences extend beyond corporate balance sheets. Credit scarcity constrains investment, productivity, and employment; weakens local supply chains; and benefits companies that already hold substantial cash reserves or have direct access to capital markets. Financial concentration therefore fuels industrial concentration. The strongest players can acquire businesses and competitors at discounted prices, while others postpone innovation or leave the market altogether. This creates a self-reinforcing cycle: large firms can raise capital more easily and, as a result, grow further, accumulate liquidity, gain inclusion in stock market indices, and attract additional capital inflows.
Markets and ownership: Finance in a few hands
This is what we are observing with growing concern in stock markets. In 2025, companies in the S&P 500 accounted for approximately 67 percent of the MSCI World Index’s market capitalization—that is, the capitalization of the world’s major developed stock markets. Furthermore, the total value of the U.S. stock market exceeded 220 percent of GDP (SIFMA/Bloomberg, 2025). As of September 2026, the world’s eight largest companies had a combined market value approaching $30 trillion—around twelve times the combined value of the eight largest companies in 2005. Seven are American, and all belong, broadly speaking, to the same technology ecosystem: digital platforms, semiconductors, cloud computing, and artificial intelligence. Concentration therefore exists simultaneously across three dimensions: scale, geography, and sector.
These companies have produced extraordinary innovations. The problem arises when their size is mistaken for an absence of risk. This is reflected in exceptionally high valuation multiples: would you buy a company for more than 100 times its revenue? At one point, this was the case with SpaceX. A global index that depends heavily on a few companies—which are themselves tied to the same investment cycle—is not as diversified as its name suggests.
The growth of passive investment vehicles can reinforce this mechanism: the greater a company’s weight in an index, the more capital it receives from funds that track that index; and the more capital it receives, the further its weight may increase. Price thus becomes, at least in part, a driver of new demand rather than merely a reflection of fundamentals.
Another form of concentration cannot be ignored: ownership concentration. Major international asset managers are simultaneously among the largest shareholders of numerous companies. OECD data show that, even in markets where ownership is more widely dispersed—the United States, the United Kingdom, Canada, and Japan—the three largest shareholders hold, on average, between 25 and 30 percent of the shares in each listed company, while the twenty largest collectively hold 50–60 percent (OECD, 2019). Alongside these funds are founders such as Elon Musk and Jeff Bezos, whose personal fortunes have reached levels once associated only with nations. Personal wealth cannot simply be equated with corporate value, but the comparison helps convey the order of magnitude. A capital increase equivalent to just 10 percent of the market capitalization of the ten largest companies would raise nearly $3 trillion—almost twice the value of the entire listed European banking sector (based on SIFMA/Bloomberg, 2025). When a small number of entities wield such financial power, the boundary between markets and power becomes blurred.
The combination of these forms of concentration also alters the relationship between finance and society. If financial wealth grows primarily through a small number of securities held mainly by the wealthiest segments of the population, the gap widens between those who benefit from asset appreciation and those who depend primarily on earned income. Similarly, if small businesses have limited access to capital, economic opportunities become concentrated in a few regions and professions. If public debt absorbs a growing share of savings, less capital remains available to finance new projects. And if these same corporate giants control digital infrastructure, data, and computing power, economic concentration also becomes a concentration of information and, inevitably, political power.
Financial stability cannot be separated from social cohesion. A system in which gains remain in the hands of a few while society bears the adverse consequences of concentration generates discontent and mistrust. These sentiments intensify when certain entities are too large, interconnected, or strategically important to fail, because market discipline can no longer operate fully. Yet the implicit protection afforded to major players imposes costs on everyone else: it reduces competition, encourages further leverage, and increases the likelihood of public intervention. The risk is not merely another financial crisis, but the gradual erosion of the economic system’s legitimacy and credibility.
Building alternatives to concentration
What should be done? The answer lies neither in penalizing scale nor in longing for small, protected markets, but in developing alternatives to concentration. Europe must complete the integration of its capital markets by promoting bond issues—including medium-sized ones—private placements, minibonds, transparent securitizations, and diversified credit funds. It must also fully support access to venture capital. Pension funds, social security funds, and insurance companies can and should finance a larger share of Europe’s productive economy, provided they do so with expertise, transparency, and risk-adjusted returns. However, dependence on banks must not simply be replaced by dependence on a few large private funds or by less transparent forms of private credit.
Entrepreneurs and executives must also change their perspective. Diversifying funding sources before they are needed, staggering maturities, maintaining liquidity reserves, and cultivating relationships with different investors are not costly precautions; they are investments in business continuity and risk mitigation. Governments need credible debt trajectories, balanced maturity profiles, and institutions capable of preserving confidence without depending on the markets’ short-term goodwill. Supervisors must consider the entire financial system—banks, funds, insurance companies, private credit, and derivatives—because risk transferred off a balance sheet does not disappear; it often simply becomes less transparent.
Finally, competition must be protected. Antitrust policies, interoperability, data portability, accessible public markets, and effective governance rules are not barriers to innovation; they prevent today’s innovation from becoming tomorrow’s rent-seeking. A vibrant economy must enable new competitors, medium-sized businesses, and peripheral regions to secure capital and room to grow when they merit it. Diversification is not merely a portfolio strategy. It is sound industrial and social policy, a form of systemic insurance, and ultimately a prerequisite for economic democracy.
For years, our primary concern has been with entities deemed too big to fail. Today, we should also be concerned about systems that are too concentrated to absorb a single mistake. When everyone depends on the same debtors, securities, intermediaries, technologies, and ultimately the same individuals wielding immense power, it does not take a momentous event to trigger a major crisis; one of the few shared pillars simply needs to fail. The success of a free-market economy lies not in entrusting everything to the winner of the moment, but in preserving enough diversity to ensure that one failure does not lead to collapse for everyone.
References
ECB (2025a), Supervisory Banking Statistics, Fourth Quarter 2025.
ECB (2025a), Survey on the Access to Finance of Enterprises, fourth quarter 2025.
IMF (2026), Fiscal Monitor, April 2026.
OECD (2019), Owners of the World’s Listed Companies.
OECD (2023–2025), Corporate Governance Factbook, 2023 and 2025 editions.
OECD (2026), Global Debt Report 2026.
SIFMA (2025–2026), Capital Markets Fact Book; data from Bloomberg.
Photo iStock / Ben Slater
