Periods of rapid equity-market appreciation are often discussed in isolation from the monetary environment in which they occur. Yet the relationship between asset values and the stock of liquid money can provide an additional perspective on how aggressively financial assets are being valued relative to the liquidity available in the economy. On this measure, the current US equity market stands out. The ratio of S&P 500 market capitalization to M2 has risen to approximately 3.0x in 2026, compared with roughly 1.9x in 2001, shortly after the peak of the dot-com cycle. That represents an increase of approximately 55.9% between the two reference points.

The comparison does not, by itself, establish that US equities are in a bubble. M2 is not a valuation denominator in the same sense as corporate earnings, free cash flow or book value, and there is no theoretical equilibrium level to which the market-cap-to-M2 ratio must revert. Nevertheless, the measure is useful as an indicator of the scale of equity valuations relative to broad monetary liquidity. Viewed through that lens, the present market is pricing substantially more corporate equity value for each dollar of M2 than it did around the technology boom of the late 1990s and early 2000s.

The historical pattern is instructive. At the beginning of the century, the ratio was elevated as technology valuations surged, before declining sharply following the collapse of the dot-com boom. It subsequently recovered during the mid-2000s expansion but fell again during the global financial crisis, reaching its lowest point in the series around 2008. From there, the ratio entered a prolonged upward trend, supported by rising corporate earnings, falling discount rates and expanding equity valuations.

The pandemic initially produced a different dynamic. M2 expanded at an exceptional rate as fiscal transfers, central-bank asset purchases and precautionary saving increased deposits across the US economy. Between 2019 and 2021, the stock of M2 rose dramatically, temporarily restraining the market-cap-to-liquidity ratio despite strong equity-market performance. In other words, both the numerator and denominator expanded rapidly.

That relationship has changed since 2022. M2 growth slowed materially and briefly reversed, while US equity capitalization resumed its advance. The result has been a pronounced increase in the ratio. By 2024–26, S&P 500 market capitalization was expanding considerably faster than the broad monetary base against which it is being compared.

The divergence is particularly relevant when considering the current artificial-intelligence investment cycle. Equity-market gains have become increasingly associated with expectations that AI will generate substantial productivity improvements, new revenue pools and stronger margins across parts of the corporate sector. Those expectations have translated into large increases in the market capitalization of semiconductor producers, hyperscalers and other technology companies exposed to AI infrastructure and deployment.

There is, however, an important distinction between today's environment and the dot-com period. Many of the companies driving current index performance are highly profitable incumbents with substantial revenues, cash balances and free cash flow. The late-1990s technology boom included a much larger universe of businesses whose valuations depended on distant or uncertain future profits. Consequently, a high market-cap-to-M2 ratio cannot be interpreted as evidence that today's equity market is simply repeating the structure of 2000.

At the same time, the liquidity comparison highlights how demanding current valuations have become. The extraordinary increase in M2 during 2020–21 created a large pool of monetary liquidity, but the subsequent rise in equity capitalization has now substantially exceeded that expansion. The market is therefore no longer simply appreciating alongside a rapidly growing stock of money. Instead, the value assigned to listed companies has increased significantly relative to it.

That distinction matters because monetary liquidity was an unusually powerful tailwind during the pandemic-era market cycle. With M2 now growing at a much slower pace, further increases in the market-cap-to-M2 ratio would increasingly need to be supported by other factors: sustained earnings growth, productivity improvements, falling discount rates, or continued multiple expansion.

The appropriate conclusion is therefore not that the current AI cycle is necessarily equivalent to the dot-com bubble. Rather, the comparison shows that US equity capitalization has reached an unusually high level relative to broad monetary liquidity. The approximately 3.0x market-cap-to-M2 ratio in 2026, versus about 1.9x around 2001, indicates that today's market is operating with materially more equity value per unit of money supply than during the previous technology boom. Whether that divergence proves sustainable will depend less on liquidity expansion than on the ability of corporate fundamentals—particularly earnings and cash flows—to catch up with the expectations already embedded in market prices.

Board of Governors of the Federal Reserve System (US), M2 [WM2NS], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/WM2NS, October 2, 2026.

Finhacker. (2026). Largest 20 S&P 500 Companies by Market Cap (1989–2026). https://www.finhacker.cz/en/top-20-sp-500-companies-by-market-cap/