How the JSE All Share changed over three decades

No index globally is static. Indices change over time, and just as the S&P 500 is now heavily weighted to technology stocks, so too, the FTSE/JSE All Share Index (Alsi) has seen relative weights of its constituents shift. As at February 2026, the so-called ‘Magnificent Seven’ (Nvidia, Alphabet, Apple, Microsoft, Amazon, Meta and Tesla) represent 34.3% of the S&P 500, up from just 12.5% a decade prior.

Locally, as Anchor Capital points out, gold and platinum shares account for more than 25% of the Alsi (with gold at about 17% at the end of 2025 from only 2% in 2022, and platinum at around 10%) – which adds a “significant amount of risk” to the JSE, “not just from a forecasting perspective, from a volatility perspective as well”. Research from Allan Gray shows that as South Africa’s economy has diversified (away from mining) over time, so too has its markets. “The top 10 shares have always dominated the Alsi, but the market leaders and sector compositions have shifted over time,” writes Matthew Patterson.

“In 1990, the market leaders were resource companies with a few industrial heavyweights.” At that time, all of the top 10 with the exception of Richemont, SA Breweries, Sasol and Rembrandt were resources shares. Dimension Data’s entry in 2000 was a result of the dot-com boom (the bubble burst a year later). This also explains Nedcor’s appearance at the time as it held 8% of Dimension Data at its IPO in London.

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These days, the “10 largest companies by market capitalisation still account for about half of the market, but with greater sector diversification and much fewer cross-holdings”. Patterson says the composition of the 10 largest shares changes regularly, but within a relatively small group. “Of the top 10 in 1990, only Anglo American has remained a consistent member of this elite group. Since the modern Alsi was launched in 2002, only 24 unique shares have featured in the top 10.” Patterson says the “the Alsi’s evolution is not just about individual companies; it also reflects dramatic sector shifts”.

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