The Takeaway
SpaceX, the largest IPO to date, had a smaller-than-expected turnover impact, underscoring the methodology’s ability to manage major market events.
June–September performance highlighted diversification’s value, as micro-cap and value stocks outperformed large-cap and growth stocks.
Concentration remained elevated: the 10 largest companies made up 35% of the Morningstar Total Market Index, with SpaceX adding further pressure.
Mega- to mid-cap packeting continued to reflect AI-driven trades from March to June and increased concentration, while small- to micro-cap movement reflected broader market dynamics.
Large-cap style packeting reflected updated growth fundamentals, not just valuation shifts. Intel, Applied Materials, Dell, and Corning moved toward growth; McDonald’s, Uber, Adobe, and Intuit moved toward value.
The Morningstar Market Indexes completed their September reconstitution. With more than $3 trillion in investor assets, including over $2 trillion linked to the Morningstar US Total Market Index, this quarterly update is important for investors, asset managers, and other market participants.
To reflect changing markets, the Morningstar Market Indexes are reconstituted quarterly through a transparent, rules-based process that refreshes membership and weights using the latest company-level data. The September ranking incorporated eight fast-track IPOs, more than 20 seasoned IPOs, about 40 mergers, 50 secondary offerings, and over 1,300 dividends, while reviewing more than 3,800 companies for updated share and fundamental data.
The September 2026 reconstitution was shaped by SpaceX’s public listing, one of the most significant market events in recent history. While its IPO increased concentration and shifted capitalization breakpoints, the Morningstar Market Indexes methodology absorbed its impact in a measured, transparent way.
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