When "Finance" Corrodes the "Real Economy"In our daily lives, we buy and sell goods and services, earning income through work. This is the "real economy" — the one directly connected to how we live. Its scale is measured by GDP (Gross Domestic Product). Alongside it exists the "financial economy," where stocks, bonds, mutual funds, and the increasingly prominent cryptocurrency assets are traded. This is measured by the total volume of financial assets and transactions — a second, enormous economic sphere.These two economies are deeply intertwined, but when the balance of their relative sizes breaks down, it can inflict serious distortions on the economy as a whole. I would like to examine this fundamentally important question: what constitutes a healthy ratio between the real economy and the financial economy?The Shadow That Has Been Allowed to GrowThe global financial economy has expanded far faster than the real economy over the past several decades. Consider the numbers. Japan's GDP — the measure of its real economy — has hovered around 500 trillion yen. Against this, Japan's total financial asset balance, as reported by the Bank of Japan, exceeded approximately 2,200 trillion yen as of March 2024. A simple comparison reveals that the financial economy is roughly 4.4 times the size of the real economy. When household financial assets alone — stocks, bonds, foreign currency deposits — exceed 2,100 trillion yen, and corporate financial assets and interbank transactions are added on top, the total becomes even more staggering.This is not a uniquely Japanese phenomenon. Global GDP stands at roughly 100 trillion dollars, while total global financial assets are said to exceed 350 trillion dollars — a ratio of approximately 3.5 to 1. The derivatives market pushes this further still: its notional value is said to be tens of times, sometimes more than a hundred times, global GDP. The scale defies imagination.This ballooning of the financial economy cannot be dismissed simply as the natural progression of financialization. It shows signs of what might be called the "autonomization of finance" — a drift away from finance's original purpose of channeling funds into the real economy, toward financial activity that generates profit as an end in itself.Several factors have driven this expansion. Globalization has accelerated cross-border capital flows. Advances in information technology have enabled algorithmic trading and high-frequency trading (HFT), where hundreds of millions of dollars can move in microseconds. Financial deregulation has spawned ever more complex new instruments — securitized products like subprime loans being a prominent example. Prolonged low interest rates squeezed bank margins and pushed institutions toward higher-risk financial activities. And the growth of shadow banking — non-bank financial intermediaries operating outside regulatory oversight — has inflated the financial economy while concealing systemic risk from view.These factors have combined to allow financial markets to expand under their own logic, largely independent of real economic growth.Bubbles, Inequality, and ZombificationWhat happens when the ratio of financial to real economy becomes unhealthily distorted?The most visible consequence is the emergence and collapse of asset bubbles. Excessive capital flows into financial markets can drive stock prices and real estate valuations far beyond what real economic growth or corporate earnings can justify. When these bubbles burst, bad debts accumulate at financial institutions, credit contracts, and the real economy suffers severe damage. The 2008 Lehman shock is the archetypal example: a financial crisis rooted in securitized mortgage products dragged real economies around the world into a severe downturn. In Japan, total financial assets swelled to nearly five times GDP during the late-1980s bubble, and the subsequent collapse is widely cited as a contributing cause of the "lost three decades." Vigilance is warranted today as well, given asset price appreciation in certain real estate markets and emerging economies that far outpaces underlying economic growth.The expansion of the financial economy also widens income and wealth inequality. The returns available through financial transactions vastly exceed what labor income can generate, and can create enormous wealth in short periods. Those wealthy enough to hold substantial financial assets — equities, property — ride bull markets to ever-greater riches, while those dependent on earned income face only rising inflation and living costs, unable to share in the gains. The result is a compounding divergence in wealth accumulation between asset-owners and non-owners, one that tends to become self-reinforcing. This suppresses the economy-wide propensity to consume, potentially impeding real economic growth, and points to a failure of redistribution that risks destabilizing society.An oversized financial economy also draws talented people and capital away from the real economy. The prospect of high compensation lures many of the most capable minds into finance, diverting intelligence that would otherwise be directed toward manufacturing, services, research, and development — the foundations of productive economic life — into what amounts to a financial money game. This risks eroding precisely the innovative capacity and productivity growth that a healthy real economy requires.Finally, the bloating of the financial economy under sustained low interest rates has enabled the survival of "zombie companies" — inefficient firms that should have been weeded out by market competition but can continue to access cheap financing and limp on indefinitely. This crowds out healthier companies, stagnates the turnover of industries, and impairs economy-wide productivity gains. When finance ceases to enforce real economic discipline, the entire economy's capacity for renewal atrophies.Toward an Ideal Ratio: The Case for 1 to 2–3So what constitutes a healthy ratio between the real and financial economy? The conventional answer is that no definitive "golden ratio" exists. Economists and researchers debate the question extensively without converging on a specific figure, because the appropriate ratio varies with each country's economic structure, stage of development, financial system, and historical moment.Nevertheless, drawing on data from past crises and periods of stable growth, and on what finance is actually supposed to do, I would like to propose one tentative benchmark: total financial assets at roughly two to three times GDP.There are several reasons to regard this range as a useful target.Finance as servant of the real economy. Finance is the circulatory system of the economy, performing essential functions — supplying capital to businesses, distributing risk, facilitating payments — that enhance efficiency and growth across the system as a whole. Financial assets at two to three times GDP represent a scale sufficient to fund the real economy, hedge its risks, and support efficient transactions, without enabling the kind of speculative excess or autonomous self-expansion that larger ratios tend to produce.Bubble prevention and systemic stability. Analyzing past bubbles and financial crises, one finds that they typically followed periods in which the financial economy had expanded to four, five, or more times the size of the real economy. Japan's bubble, as noted, was approaching a ratio of five before it collapsed. A ratio in the two-to-three range serves as a safety valve — reducing the likelihood that asset prices will diverge dramatically from economic fundamentals and making it easier to sustain overall financial system stability.Efficient capital allocation. At two to three times GDP, capital is more likely to flow toward genuinely productive uses in the real economy. Excess financial assets tend to encourage speculative misallocation and sustain zombie firms; keeping the ratio within bounds helps restore the mechanism by which capital finds its way to where it is actually needed.Recycling returns into innovation. At this scale, profits generated in financial markets are more likely to be reinvested productively into the real economy — particularly into research, development, and new technologies. Finance can function as an engine of the real economy rather than a drain on it. Venture capital channeled appropriately to startups provides one example of this dynamic working as it should.This "two to three times" figure is, of course, a hypothesis rather than a law, and it may need to be revised as technology and economic systems evolve. If blockchain technology were to dramatically increase the transparency and efficiency of financial transactions, enabling a more direct and verifiable circulation of funds, it is conceivable that the financial economy could be somewhat larger than this while still maintaining healthy linkages to the real economy.A Path Toward RebalancingWhat can be done to rein in financial excess and restore a healthier relationship between the two economies?Strengthening and reconstructing financial regulation. Regulatory frameworks have tightened since the Lehman shock, but the oversight of shadow banking and new digital financial instruments — particularly unregulated crypto-linked derivatives — remains inadequate. Stricter capital requirements for financial institutions, greater transparency in derivatives markets, and regulatory frameworks that keep pace with evolving financial technology are all essential. International coordination is also necessary to prevent regulatory arbitrage. The risk management challenges posed by AI-driven high-frequency trading are among the most pressing immediate concerns.Creating stronger incentives for real-economy investment. Policy measures are needed to encourage capital to flow toward productive investment rather than financial markets. These might include tax incentives for research and development, improved access to risk capital for startups, stronger financing support for small and medium enterprises, and strategically directed public investment in future growth industries. When finance is policy-steered back toward its proper role as servant of the real economy, the conditions for sustainable growth improve.Financial literacy and sound asset formation. Individuals need sufficient understanding of how financial markets work to make sound investment decisions. Ignorance of new financial instruments, including cryptocurrencies, can fuel reckless speculation and add to systemic instability. Promoting long-term, diversified, systematic investing helps create a more stable foundation of household wealth that does not depend on speculative swings.Ethical finance and ESG investment. Financial institutions and investors should be encouraged to pursue responsible investment — incorporating environmental, social, and governance (ESG) criteria alongside short-term financial returns. Finance should aspire to be a force for broader social sustainability, and the growing recognition that ESG considerations also enhance long-term corporate value is a constructive development in this direction.Continuing corporate governance reform. Companies should be encouraged not merely to accumulate internal reserves, but to balance shareholder returns with genuine investment in growth and in their employees. The goal is to ensure that corporate profits flow back into productive economic activity rather than pooling in financial markets.The Art of Balance and Our Responsibility to the FutureThe ratio of real to financial economy is a crucial indicator of economic health. Even if no single figure can be declared the golden ratio, a financial economy that has drifted from its purpose as servant of the real economy — that has grown autonomous and self-referential — will reliably produce distortion and instability.My proposal of total financial assets at roughly two to three times GDP is only a benchmark. But naming a benchmark gives us a starting point: a way to sound the alarm about the tendency of finance to grow as a "shadow economy," and to ground concrete policy debate about what it would take to restore and maintain a healthier balance.We must learn from the lessons of past bubbles and crises, and continue to pursue what might be called the art of balance — ensuring that the financial economy supports rather than overwhelms the healthy growth of the real economy. This is not merely a matter of economic policy. It is a philosophical challenge: a call for each of us to reconsider our relationship with money and to think seriously about what we actually value in our economic life together.To embrace the benefits that financial innovation can bring, while remaining vigilant against the risks of its excess, and to pursue a sustainable prosperity rooted in the real economy — this is the most important perspective our era demands of us, and our most fundamental responsibility to the generations that follow.SourcesBank of Japan Institute for Monetary and Economic Studies — research on the divergence between financial and real economiesInternational Monetary Fund (IMF) — Global Financial Stability ReportFinancial Stability Board (FSB) — reports on shadow bankingOrganisation for Economic Co-operation and Development (OECD) — research on financial policy and economic growthAcademic research on asset price bubbles and their economic effectsResearch institution reports on ESG investment and corporate sustainabilityBank of Japan Flow of Funds StatisticsCabinet Office of Japan, National Accounts (GDP Statistics)S&P Global, McKinsey & Company and other analytical reports on global financial assets and GDP