Across most of the world, governments have been accumulating debt at an accelerated pace over the past two decades, whether to finance social policies, fund military expenditures, or stimulate the economy and protect the private sector during critical moments. In all cases, public indebtedness has become a growing challenge, and its effects, though not always visible in the short term, must be treated with seriousness.
Source: World Economic Outlook (FMI), Turim
The global stock of public debt, which had already increased substantially following the Global Financial Crisis of 2008, expanded even further after the pandemic in 2020. This occurred not only because of the unprecedented fiscal stimulus implemented by many economies, but also due to rising interest rates, which significantly increased the cost of rolling over government bonds. The most recent estimates from the International Monetary Fund (IMF) project that public debt will exceed 100% of global GDP by 2029, the highest level since the post-war period in 1948. It is worth noting that, historically, these projections have tended to underestimate the actual growth of debt.
In this letter, we discuss the roles of fiscal policy, the main challenges faced by governments today, and possible paths for course correction, considering their aggregate and distributive effects on the economy and population well-being, as well as their implications for markets and investment management. For investors and wealth managers, understanding the dynamics of public debt is essential, as it directly influences interest rates, inflation, and the pricing of global assets.
The Benefits of Debt and the Cost of Default
Debt is not necessarily a bad thing. On the contrary, academic consensus points to an optimal level of indebtedness, whether in public or private management, at which the benefits of leverage outweigh its costs. Even net creditors, such as countries that hold sovereign funds exceeding their financing needs, issue sovereign bonds to access credit.
Among the legitimate reasons for public borrowing, we can highlight:
- Intertemporal tax smoothing, which allows governments to distribute the cost of large expenditures over time and avoid abrupt tax increases that could create economic distortions.
- Financing productive investments, such as infrastructure, that generate long-term social and economic returns.
- Creating a local benchmark for interest rates, which contributes to the development and stability of the financial system.
- Using fiscal stimulus in critical periods, serving as a tool to smooth economic cycles, especially when monetary policy options are limited.
However, when debt reaches unsustainable levels, governments may feel tempted or even forced to fail to meet their fiduciary obligations, leading to a default. A default occurs when a government fails to meet its contractual debt obligations, whether through delay, suspension, or restructuring under less favorable terms for creditors. While the formal definition may vary, a default can generally be understood as any event that reduces the value received by creditors. According to IMF specialists, these events can be categorized as technical, contractual, or substantive defaults (Ams, J. et al., 2018), reflecting different degrees of noncompliance.
Source: AMS, J. et al. (2018)
What may initially seem like an easy solution actually entails several costs for the country, such as the loss of access to financial markets, both domestic and international. This loss translates into higher financing costs, exclusion from benchmark indices, and credit rating downgrades. Although some countries have regained market access years later, severe or prolonged defaults have often led to persistently higher risk premiums.
There are also economic side effects, such as sharp GDP contractions, declines in international trade, and lower inflows of foreign investment. Domestic companies may also face declines in market value and more restricted credit access. Among the most affected sectors is banking, which frequently holds large volumes of public debt securities and suffers losses that may compromise financial stability, leading to credit crises and prolonged recessions.
Finally, legal costs, resulting from litigation and contractual disputes, can also be significant. A well-known example is that of the holdouts (creditors who refused restructuring offers) in Argentina, which faced court battles for more than a decade following the 2001 default. Although international sovereign debt laws have advanced considerably since then, such cases show that default tends to be a government’s last resort, used only in situations of unavoidable insolvency.
Determinants of Sustainability and Solvency
Formally, the assessment of fiscal sustainability begins with the non-Ponzi condition1, which states that a government cannot indefinitely finance itself by issuing new debt to pay off old debt. In other words, all debt incurred must eventually be repaid through the government’s own revenues. This implies that the present value of all future public revenues must be equal to or greater than the sum of future expenditures and the existing stock of debt, adjusted for the cost of carry.
From this perspective, the determinants of fiscal sustainability can be summarized in three key components that govern the dynamics of public debt as a percentage of GDP:
- Primary balance: the difference between revenues and expenditures, excluding interest payments on the debt
- Cost of debt: the interest expense, which depends on the size of the debt and the effective rate applied to government securities
- Economic growth: the main driver of tax revenue growth and the denominator in the debt-to-GDP ratio.
It becomes clear that countries in which the rate of economic growth exceeds the interest rate applied to public debt enjoy greater flexibility to adjust fiscal policy (r−g<0). In the opposite case, maintaining a stable debt-to-GDP ratio requires a certain degree of fiscal effort, such as generating a primary surplus. This point has become particularly challenging in recent years, given the combination of higher interest rates and already elevated global indebtedness.
History, however, offers examples of successful course adjustments achieved even in high-debt environments without default. A comprehensive study by Abbas, S. M. A. et al. (2011) analyzed large reductions in debt-to-GDP ratios across various countries, breaking down the factors that contributed to these adjustments. The same methodology was later used by other authors, including Best, T. et al. (2018), from which the following chart was adapted.
Source: BEST, T. et al. (2018)
In general, the authors show that there was no single “silver bullet” solution, but rather a combination of factors, each contributing to different degrees depending on each country’s circumstances and the global context. In advanced economies before World War I, debt reductions were mainly achieved through primary surpluses in an environment of modest growth and low inflation. In the interwar period, successful adjustments resulted from a combination of hyperinflation and primary surpluses, while in the post–World War II era, debt reduction was predominantly associated with negative interest-growth differentials in a context of rapid growth, financial repression, and persistent inflation.
It is worth noting that sovereign defaults are almost always triggered by a solvency crisis, meaning a situation in which the government can no longer obtain sufficient credit to roll over its debt, rather than by a voluntary decision based solely on perceived unsustainability. Naturally, this tends to happen when markets anticipate a sustainability crisis.
It is also possible for liquidity crises to occur, caused by temporary shocks such as periods of heightened global risk aversion. These situations, however, are generally manageable through credit lines provided by multilateral institutions such as the IMF. In much rarer cases, a country may repudiate its debt, claiming not to recognize its legitimacy, as the Soviets did after the 1917 Revolution that ended the Tsarist regime. However, this mechanism is rarely used today because of the significant reputational and legal costs involved, especially in international markets, where such actions find little precedent.
Therefore, the most important objective is to ensure that the expected trajectory of public debt remains non-explosive, allowing moderate inflation and economic growth to help reduce the real burden of debt and enable refinancing at sustainable levels. With that in mind, the following sections analyze possible approaches to addressing the current global fiscal challenges.
The Path of Austerity and the Social Challenge
Fiscal consolidation is often the first recommendation to restore confidence and stabilize public debt. This approach, aligned with the spirit of the Washington Consensus2, is based on the idea that cutting expenditures and/or increasing revenues is the safest way to balance public finances. It is important to highlight that this path is discretionary by definition, meaning that passive improvements in the fiscal position, resulting from favorable macroeconomic conditions such as higher-than-expected growth or lower interest rates, should not be counted. Thus, the consolidation effort is typically measured by changes in the cyclically adjusted primary balance.
However, implementing such measures is often much more complex than theory suggests. The first challenge concerns timing, since fiscal tightening tends to suppress economic activity in the short term. From a country risk perspective, beyond its direct contribution to the debt-to-GDP ratio, the impact on economic activity also reduces the tax base and can activate other “automatic stabilizers3”, such as higher demand for unemployment insurance and social benefits.
From a social perspective, the contraction in activity affects population well-being and inevitably carries political consequences. Because the cost of adjustment is immediate while the benefits only materialize in the medium and long term, the electoral cycle often favors short-term or palliative solutions. There are also relevant technical challenges, such as budget rigidity: mandatory expenditures, including public sector wages and pension and social benefits, often follow complex legal rules that can only be changed through structural reforms that are difficult to approve. Social security is one of the most emblematic cases, as population aging has increased the number of beneficiaries and reduced the share of contributors in almost every country, putting pressure on the system’s sustainability.
These challenges are aggravated by a complex global socioeconomic environment, characterized by a high cost of living (as reflected in the difficulty of entering the housing market), a decline in the marginal return of education (with increasingly educated generations earning less than previous ones), and uncertainty regarding the sustainability of social programs, such as pension systems, which cast doubt on the right to retirement for younger generations.
This deterioration in expectations undermines confidence in institutions and reduces tolerance for policies that demand immediate sacrifices in exchange for future gains, creating fertile ground for the emergence of demagogic political leadership.
The Erosion of Currency Value and Financial Repression
When public debt is denominated in domestic currency, as is the case for most countries today, the rules of the game become more flexible. This is not only because local legislation does not require the same degree of contractual robustness — allowing alternative forms of debt repayment, such as changes in currency or indexation — but also because, ultimately, the government can issue money to meet its obligations.
A brief historical overview helps illustrate this dynamic. The use of monetary expansion as a means of financing the State dates back to the era of metallic currencies, which lasted until the eighteenth century in the West. Records from the Roman Empire in the third century BCE already show a reduction in coin purity through the mixing of less valuable metals, thereby increasing the money supply at the cost of greater inflationary pressure. This practice, known as currency debasement, became recurrent in the following centuries and eventually represented a significant source of state revenue.
In more recent history, after a period of broad monetary expansion during the so-called Age of Catastrophes (1914–1945), the Bretton Woods Agreement served as a temporary brake on currency debasement by pegging the value of the US dollar to gold and that of other currencies to the dollar. Following the collapse of that system in 1971, a new era of purely fiat currencies began, granting governments wide flexibility to issue money at a time when both the cost and time required to do so had fallen dramatically.
It is important to note that monetary expansion and seigniorage—the revenue a government earns from issuing money — are not, by themselves, problematic, as long as they occur at moderate levels and in alignment with monetary policy. When managed appropriately, they can meet liquidity needs and help smooth cyclical fluctuations in the economy. The problem arises when money creation is used to finance fiscal deficits, a practice that has historically led to hyperinflationary crises, such as those observed in Venezuela and Zimbabwe. Moreover, unexpected inflation has a redistributive effect between creditors and debtors (including the government itself) by eroding the real value of debt.
The growing demand for inflation-linked bonds has reduced the potential gains from such inflationary strategies, but it has not eliminated the risk of financial repression, used to artificially depress interest rates. Recent examples include Argentina (from 2010 onward) and Turkey (since 2018), where real interest rates remained negative for extended periods. In Argentina’s case, even the official inflation statistics were manipulated, underestimating the true pace of price increases.
While this approach may appear effective in the short term, the inflationary option (regardless of form) creates distributional distortions in wealth and can erode credibility if sustained over time. In addition to redistributing income between creditors and debtors, inflation has a regressive social impact, disproportionately affecting those without access to indexation mechanisms, typically the poorest segments of the population. In contrast, individuals and institutions with more resources tend to seek stores of value, including financial assets denominated in hard currencies (when the risk is country-specific) or real assets such as real estate, equities of companies with strong cash flow and pricing power, and commodities — particularly precious metals.
It is therefore unsurprising that the performance of gold has stood out in recent years, although other factors have also contributed to this phenomenon. Among them are the increased demand for physical gold by central banks, particularly after the United States decided to freeze Russia’s international reserves following the invasion of Ukraine in 2022, and the subsequent trend toward deglobalization observed since early that year4.
Source: Macrobond, Turim
The Hope of Productivity
As discussed earlier, economic growth is also a mechanism for containing the debt burden. However, the policies typically recommended in this area aim to increase potential output through investment in infrastructure, human capital development, and reforms that improve the business environment. These initiatives naturally produce results only in the long term, thus playing a complementary role in the fiscal debate.
In some developing countries, the relatively low level of basic infrastructure — such as public sanitation and urbanization — still provides significant opportunities for growth, large enough to justify recurring fiscal deficits over extended periods without undermining sustainability metrics. India is a prominent example, having made substantial progress in this regard in recent years. However, this strategy is not viable for most countries, especially advanced economies, where structural growth potential is more limited.
Nevertheless, not all is lost. The Nobel Prize in Economics this year was awarded to Joel Mokyr, Philippe Aghion, and Peter Howitt for their contributions to understanding innovation as a driver of economic growth. The central idea is that incorporating new technologies into the production sector creates space for more efficient forms of production. This school of thought, pioneered by Austrian economist Joseph Schumpeter, who popularized the concept of creative destruction, attributes the rapid growth of the past two centuries to this process, which has drastically reduced poverty and raised global living standards.
Source: OpenAI, World Bank, Turim
The topic is especially relevant today, not only because of its immediate connection to the exponential growth of artificial intelligence (AI) over the past three years, but also because it may represent a light at the end of the tunnel for public finances.
Estimates of AI’s potential impact on productivity vary widely. The most optimistic projections suggest a boost of up to 7% over the next decade, while more cautious perspectives, such as that of Daron Acemoglu — author of Why Nations Fail and recipient of the 2024 Nobel Prize in Economics — acknowledge a “nontrivial but modest” impact, limited to 0.71% in total factor productivity over ten years, while noting that even this estimate may be overstated.
Society and Markets
Although there is no single solution applicable to all cases, the most advisable path seems to be a balance between responsible fiscal governance and policies that foster a favorable environment for economic growth. With some degree of luck, productivity gains may help ease the burden of debt, creating room for a healthier cycle of expansion.
At the opposite end of possible scenarios lies an increasingly unsustainable trajectory, culminating in a process of restructuring or the adoption of “creative solutions.” These could include inflationary surprises and instruments of financial repression, potentially even yield curve control policies such as those implemented in Japan since 2016.
In the most optimistic scenario, we can envision a period of robust growth combined with moderate inflationary pressures. This type of growth, driven by capital and innovation, could reinforce the trend toward wealth concentration, but would still be net positive for society, as it would raise productivity and overall living standards, even if some sectors were “destroyed by innovation” and certain workers required reallocation. Under these conditions, risk assets, particularly equities, tend to perform better.
In a less favorable scenario, confidence in fiat currencies and traditional institutions would be shaken, resulting in more persistent inflation and the risk of a new “lost decade,” similar to what several Latin American countries experienced after the crises of the 1980s. Even before an eventual collapse, investors would likely demand higher risk premiums on traditional assets such as bonds and equities, while alternative stores of value (such as precious metals and crypto assets) could gain a larger share in global portfolios and even in financial transactions.
Whatever the outcome, it will not become evident in the short term, nor will it follow a linear path. The most likely scenario is that the world will remain, for some time, in a state of uncomfortably high global indebtedness, with partially anchored expectations and opportunistic fiscal adjustments, alternating with periods of heightened risk aversion.
These shifts in narrative will likely continue to generate volatility in asset prices, reinforcing the importance of diversification and long-term discipline.
Referências
ABBAS, S. M. A. et al. Historical Patterns and Dynamics of Public Debt — Evidence from a New Database. International Monetary Fund, May 2011.
ACEMOGLU, D. The Simple Macroeconomics of AI. MIT, Massachusetts, Apr 2024.
AMS, J. et al. Sovereign Default. Washington, DC: IMF, Sep 2018.
BEST, T. et al. Reducing Debt, Short of Default. Washington, DC: IMF, Sep 2018.
EICHENGREEN, B. et al. Public Debt Through the Ages. Washington, DC: IMF, Sep 2018.
POSEN, A. Geopolitics Is Corroding Globalization. Washington, DC: IMF, Jun 2024.
GOLDMAN SACHS. Generative AI Could Raise Global GDP by 7%. Apr 2023.
