$57 Billion Just Rushed Into SPYM | Is SPY’s Cheaper Twin Finally Taking Over?

Investors poured $57 billion into SPYM in 2026, favoring its 0.02% fee over SPY's 0.0945% for identical S&P 500 exposure.

VOO and IVV match SPYM's fee advantage as core S&P 500 holdings, with brokerage access and commission-free trading typically deciding the choice.

The flow numbers tell you what buy-and-hold investors have already decided. Investors poured roughly $56.75 billion into the State Street SPDR Portfolio S&P 500 ETF ( NYSEARCA:SPYM ) so far in 2026, including about $5.2 billion over the latest month, lifting the fund beyond $170.5 billion in assets.

That is a lot of money moving into a fund most investors had never heard of two years ago. SPYM owns the same S&P 500 that the SPDR S&P 500 ETF Trust ( NYSEARCA:SPY ) has tracked since 1993. What changed is the price tag and the plumbing. SPYM charges 0.02% against SPY's 0.0945%, and it is structured as an open-end fund rather than a unit investment trust. Those two differences are quietly reshaping which funds belong in a long-term portfolio and which belong on a trading desk.

Both funds track the S&P 500, and their top holdings are essentially identical. SPYM's largest position is NVIDIA ( NASDAQ:NVDA ) at 8%, while SPY also carries NVIDIA at 8%. The rest of the top ten matches in the same order.

Because the portfolios are the same, the fund-selection question stops being about exposure and starts being about cost, structure, and how you intend to use the thing.

SPY was launched as a unit investment trust, a legal structure that forbids the manager from reinvesting dividends internally or lending securities. Cash from dividends sits uninvested until the next quarterly distribution, which creates a small but persistent drag during rising markets.

SPYM is an open-end fund. It can reinvest dividends immediately and engage in securities lending, both of which quietly help tracking. Over a long holding period, those small edges compound alongside the lower fee.

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SPY's structure, though, is precisely what makes it the deepest, most liquid equity product on earth. Its options market has no rival, and its bid-ask spreads are pennies on hundreds of dollars. Traders pay the higher expense ratio because they need that liquidity.