Abstract: Stock market concentration has surged to record levels, exceeding those of the dot-com bubble and raising growing concerns among investors and regulators. This paper provides the first cross- country evidence on the structural effect of stock market concentration on systemic financial crises. Using a panel of 30 major stock markets from 1998 to 2020 and systemic crisis episodes from the Global Crises Data by Country dataset compiled by the Behavioral Finance and Financial Stability (BFFS) project at Harvard Business School, I estimate probit models with correlated random effects (Mundlak correction) and employ a control-function IV strategy to address endogeneity concerns. The results show that higher concentration significantly increases the likelihood of systemic crises, even after controlling for established macro-financial predictors. Liquidity emerges as the key transmission channel, consistent with theories of fire sales and rapid asset liquidations under stress. Robustness checks, including alternative crisis definitions, functional forms, and instrumental variables, confirm the stability of the findings. The evidence demonstrates that stock market concentration is not merely a byproduct of financial development, but a fundamental structural driver of systemic fragility, with critical implications for the design of macroprudential policy.  

Abstract: This paper explores the relationship between financial derivatives and wealth inequality. While previous studies have acknowledged a connection between finance and inequality, the precise nature of this relationship remains uncertain. Our study aims to contribute to this discourse by isolating the impact of financial derivatives on wealth distribution, controlling for other financial factors. Using data for 15 countries from 2001–2021, we examine the relationship of exchange- traded derivatives from the Bank of International Settlements and pre-income tax wealth Gini coefficients for adults from the World Inequality Database. Employing panel econometric tech- niques and controlling for country fixed effects, we analyze the dynamic relationship between these variables. Contrary to conventional financial theory, which often views derivatives as redundant assets, our findings reveal a positive, significant and robust association between wealth inequality and the use of derivatives. This challenges prevailing assumptions and underscores the importance of derivatives in shaping global wealth distribution dynamics.

Abstract: Our paper investigates the long-term implications of stock market concentration for income dis- tribution, using a panel dataset of 46 countries between 1989 and 2016. We find that greater stock market concentration — measured by the market capitalization share of the top 10 firms is positively associated with rising income inequality. This relationship is robust across multiple measures of inequality, including the Gini coecient, the income shares of the top 1% and top 10%, and the declining share of the bottom 50%. The results hold after controlling for macroeconomic factors, financial development, and both country and time fixed effects. Our findings indicate that equity market structures have important distributive implications. Concentrated markets appear to disproportionately benefit top-income groups, reflecting unequal ownership of financial assets and the excess gains of dominant firms. At the same time, stock market concentration is associated with declining income shares for the bottom half of the population, suggesting a redistribution of economic gains from the bottom to the top. We also explore the role of financial development and uncover a non-linear, U- shaped relationship with inequality: while financial expansion reduces inequality at early stages, more advanced financial systems tend to reinforce it. This pattern, which contrasts with earlier literature on the finance-inequality nexus, may reflect recent trends in financialization and capital market dynamics that increasingly favor high-income groups.

Abstract: Financial derivatives play a growing role in shaping economic inequality, yet their impact on income distribution remains poorly understood. While wealth inequality is primarily shaped by asset accumulation and returns, income inequality reflects labor-market structures, institutional settings, and the effects of financial liberalization. Using panel data for 15 countries from 2001–2022, I examine the relationship between exchange-traded derivatives and measures of income inequality, including the Gini coefficient and percentile ratios.The findings show that derivative activity disproportionately amplifies disparities at the upper end of the income distribution, with the top 10%—and especially the top 1%—capturing most of the gains. Unlike in the case of wealth inequality, these effects are not driven by asset returns but by the interaction between derivatives markets and income channels such as executive compensation, capital–labor income shares, and financial sector wages. By highlighting these divergent mechanisms, the paper contributes to a more nuanced understanding of how derivatives reshape inequality and why income and wealth must be studied as related but fundamentally different distributions.

Abstract: The project investigates how stock market concentration shapes the buildup of systemic fragility. Relying on SRISK, a forward-looking measure of systemic vulnerability developed by Acharya et al., the analysis focuses on whether systemic exposure is disproportionately driven by dominant firms in highly concentrated equity markets. The central hypothesis is that when capitalization is skewed toward a small set of firms, aggregate SRISK becomes more sensitive to market downturns, thereby amplifying systemic fragility.The study combines SRISK estimates with cross-country data on stock market concentration and firm-level financial characteristics. An extension compares the systemic implications of equity-market concentration with those of banking-sector concentration, evaluating whether fragility is more acutely driven by dominant nonfinancial corporations or by concentrated financial institutions. By linking market structure to forward-looking measures of systemic vulnerability, the project seeks to provide new insights into how financial systems accumulate risk before crises materialize.