The American Millionaire Boom is Driven by Asset Ownership

This rapid expansion of the millionaire class is not primarily a product of high salaries, but of market participation. According to the latest annual wealth report from UBS, financial assets—specifically stocks and bonds—comprise 79% of gross wealth in the U.S. A sustained, historic run in the equity markets has acted as the primary engine for this growth, proving that long-term wealth is built through asset ownership rather than earned income.

Yet, this concentration of wealth masks a deeper fragility in the broader economy. While average household wealth climbed nearly 10% between 2020 and 2025, median wealth actually dropped by almost 20%. The data highlights a growing divergence: the millionaire boom is a reality for the affluent, but the typical American household has seen its financial standing erode over the same five-year period.