S&P 500 ETF Duo Assets Surpassed $1 Trillion

Investors holding these funds should compare expense ratios to ensure they match their long-term cost strategy.

Updated on Oct. 7, 2026 in Investing

Two tall metallic geometric shapes of different heights stand on a marble surface in an isometric editorial illustration. — Combined assets in the SPY and SPYM exchange-traded funds surpassed $1 trillion, reflecting divergent preferences for liquidity and cost-efficiency among investors. AI Illustration. Upload story photo >

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Is now a good time to prioritize low-cost ETFs over established, high-liquidity funds?

The combined assets of the SPY and SPYM exchange-traded funds have reached a milestone of over $1 trillion. This growth reflects the continued popularity of S&P 500 tracking funds among both institutional traders and individual buy-and-hold investors.

Why it matters

The milestone highlights how dual fund structures cater to different financial needs, with SPY offering high liquidity for traders while SPYM provides a lower-cost option for long-term holders. Understanding the expense structure of your holdings is essential for managing net investment returns over time.

As of October 6, 2026, SPY held $819 billion and SPYM held $179.2 billion in assets under management. Investors should note the difference in expense ratios, with SPYM at 0.02% compared to 0.09% for SPY.

The players

SPY

An exchange-traded fund tracking the S&P 500 that is structured as a unit investment trust and known for high liquidity.

SPYM

A lower-cost 1940 Act exchange-traded fund tracking the S&P 500 that launched in 2025.

VOO

A major S&P 500 tracking fund that became the world's largest ETF in February 2025.

The details

SPY, which launched in 1993, operates as a unit investment trust, while the newer SPYM is structured as a 1940 Act ETF. The lower expense ratio of SPYM is designed to reduce the annual fee drag on portfolio growth for long-term investors. Institutional participants often favor the deep liquidity of SPY, whereas retail advisors may prioritize the cost-efficiency of SPYM.

1993: SPY launched.
February 2025: VOO became the world's largest ETF.
November 2025: SPYM launched.
October 6, 2026: Combined AUM of SPY and SPYM recorded.
October 7, 2026: Combined AUM surpassed $1 trillion.

Money Landscape

This growth follows the precedent set when VOO became the world's largest ETF in early 2025. It underscores a wider trend where institutional and retail investors prioritize cost efficiency within the $24 trillion global ETF market.

If you hold S&P 500 funds, review your current expense ratio to see if lower-cost alternatives align with your long-term goals. Consult with a qualified financial professional to determine if rebalancing your holdings is appropriate for your specific tax and investment situation.

The takeaway

The $1 trillion milestone illustrates the shifting preference for lower-cost fund structures within the core S&P 500 market. Investors should regularly audit their existing holdings to confirm their current expense ratios remain competitive relative to newer fund offerings.