Miguel Antón is a Professor in the Financial Management Department at IESE Business School. This post is based on a recent paper by Professor Antón, Florian Ederer, the Allen and Kelli Questrom Professor in Markets, Public Policy & Law at Boston University, Mireia Giné, Professor and Head of the Financial Management Department at IESE Business School, and Guillermo Ramirez-Chiang, a PhD candidate in the Finance Department at IESE Business School.
Common ownership describes a situation whereby the same investors hold significant stakes in multiple competing firms. Over the last few decades it has become a defining feature of modern capital markets. Its growth has sparked an important debate among academics, regulators, and policymakers about its potential implications for competition and corporate governance.
In our new working paper “Common Ownership Around the World,” we provide the first systematic, global analysis of this trend. Using a novel dataset covering 49 countries and more than 60,000 publicly listed firms from 2005 to 2019, we document the global rise in common ownership and explore its key drivers. While common ownership is increasing across the globe, the United States remains a clear outlier in both the level and concentration of such ownership.
A Global Trend with U.S. Leadership
Our study shows that common ownership is now a global phenomenon. In the median country, the average measure of overlapping ownership (κ) more than doubled between 2005 and 2019. However, the U.S. stands far above all others: its average common ownership intensity is nearly twice as high as the next highest country. This U.S. dominance is not only due to higher institutional investment but also to greater concentration among asset managers. Notably, this pattern persists even when adjusting for firm size and industry, indicating that the U.S. is structurally distinct in its ownership architecture.
The increase in common ownership is especially pronounced among the largest firms in every country. Across regions, firms in the top tercile of the market capitalization distribution have approximately three times the level of common ownership of the median firm. This concentration means that common ownership is most intense precisely where market power and competitive dynamics are likely most consequential. In fact, in the U.S., common ownership levels among top-tercile firms are on par with those observed among S&P 500 constituents, suggesting that the trend is particularly pronounced at the upper end of the firm size distribution.
The Role of the Big Three
One of the most striking findings is the central role played by the “Big Three” asset managers—BlackRock, Vanguard, and State Street. In the U.S., these firms have become the largest shareholders in nearly 40% of all public companies, up from just 3% in 2005. Their rise accounts for a significant share of the growth in common ownership, both domestically and globally. This rise reflects both their growing assets under management and the increased popularity of passive index investing. READ MORE
