MSCI World ETF Prepares for Major Index Methodology Overhaul

The iShares MSCI World ETF’s first-quarter 2026 rebalancing was far from routine. For the first time in several years, the fund’s exposure to US equities was reduced on a net basis. Market observers note this was a deliberate preview of more substantial changes scheduled for May.

Portfolio Shifts: A Move Toward Thematic Sectors

Effective at the close of trading on February 27 and reflected in the index from March 2, the rebalancing introduced 18 new holdings while removing 27, resulting in a net contraction of the portfolio’s overall size.

A notable development was the treatment of US securities. Fifteen US stocks were deleted against only eight additions, producing the first net decrease in US weighting for multiple years. New entrants included thematic companies such as AST SpaceMobile, Coherent Corp, and FTAI Aviation, which are linked to AI hardware and satellite-based communication. In Japan, Ibiden and Shimizu were added. A prominent removal in Europe was the French payment services provider Edenred.

Despite these adjustments, US stocks continue to dominate the fund, representing over 70% of the portfolio. Nvidia remains the largest single position with an approximate 5% weighting, followed by Apple and Microsoft.

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March Rebalancing Sets the Stage for May Reform

Index provider MSCI intentionally limited the scope of the March adjustments. The reason is a comprehensive revision of the index methodology slated for May 2026. New rules for calculating free float and modified rounding conventions could significantly alter the weighting of individual mega-cap stocks. A more aggressive rebalancing in March would have forced unnecessary portfolio turnover likely to be reversed just two months later.

Also now off the table is a previously debated proposal to exclude companies with substantial cryptocurrency holdings from the index. MSCI has definitively abandoned these plans. Firms where crypto assets constitute more than 50% of total assets will remain eligible for inclusion, provided they meet all other criteria.

Key Dates for Investors

In the immediate term, investor focus turns to the Federal Reserve’s policy meeting on March 17-18. Given the portfolio’s heavy US concentration, the interest rate decision represents the most critical macroeconomic factor for the ETF’s near-term performance.

The medium-term outlook, however, hinges on the May deadline. The implementation of MSCI’s methodology reform is expected to alter the index’s composition more profoundly than all quarterly rebalancings of recent years combined.