The Invesco S&P 500 Momentum ETF (SPMO) has pulled in nearly $3.59 billion in net inflows over the past three months. See More: Mind the Momentum ETFs: SPMO, MTUM Having Strong MonthHow SPMO WorksSPMO tracks the S&P 500 Momentum Index, which selects and weights stocks based on their risk-adjusted price momentum rather than market capitalization. Unlike broader momentum strategies that draw from large- and midcap stocks, SPMO focuses exclusively on S&P 500 companies and weights holdings according to their momentum characteristics rather than their size. Compared with the broader S&P 500, momentum has also delivered a stronger result. While both ETFs seek to capture companies with strong price performance, SPMO focuses exclusively on S&P 500 companies and weights holdings based on momentum characteristics.