Combined Assets in SPY, SPYM Cross $1 Trillion for the First Time

On Wednesday, the combined assets invested in the State Street SPDR S&P 500 ETF (SPY) and the State Street SPDR Porfolio S&P 500 ETF (SPYM) passed the $1 trillion mark for the first time. SPY, the first-ever U.S.-listed ETF, and SPYM, SPY’s less expensive clone, as of the close on October 6, 2026, held $819 billion and $179.2 billion in AUM, respectively, with a bump the following day pushing them past that key milestone. Key Takeaways - State Street’s S&P 500 ETFs (SPY & SPYM) surpassed $1 trillion in combined AUM on Wednesday. - SPYM has a lower cost and lower expense ratio than SPY, making it more suitable for advisors, while SPY appeals to institutional traders. - Until last year, SPY had spent 30 years as the largest ETF in the global ETF industry. “State Street ETFs remain core building blocks for many investors. Crossing the $1 trillion milestone for these two ETFs is a testament to how widely utilized their products are by investors,” said Todd Rosenbluth, VettaFi’s head of research. SPY launched in 1993, essentially lighting the match under what has, in the more than 30 years since, become the global ETF industry, representing $24 trillion in total assets under management. SPYM is a much newer addition — and tracks the same S&P 500 Index — having launched in November 2025 and found instant acceptance among investors. SPYM crossed $100 billion in assets under management in less than a year, a remarkable growth rate. That pace of asset accumulation will no doubt be further boosted by the fund’s inclusion as the default allocation for the Trump Accounts program launched on July 4. Key Differences Between SPY, SPYM The smaller fund has a number of differences from SPY, despite delivering essentially the same performance. SPYM is a 1940 Act ETF — while SPY is structured as a unit investment trust — and comes with an expense ratio of a mere two basis points. Meanwhile, SPY charges 0.09% and has a handle almost 10 times as large as that of SPYM. The newer of the two ETFs was designed to appeal to advisors and buy-and-hold investors, with its lower per-share cost and smaller expense ratio. SPY, on the other hand, continues to appeal to traders who are less inclined to care about either the size of its trading price or expense ratio, but relish the large fund’s vast liquidity. SPY lost its crown as the largest ETF in the world to another S&P 500 ETF, the Vanguard S&P 500 ETF (VOO) in February 2025. VOO currently weighs in at $1.0 trillion in AUM on its own. For more news, information, and analysis, visit the Equity ETF Content Hub.