The Few Stocks That Powered Your IEMG Holding

June 22nd, 2026 by Trefis Team
IEMG: iShares Core MSCI Emerging Markets ETF logo
IEMG
iShares Core MSCI Emerging Markets ETF

The emerging markets fund posted a strong return, but a look under the hood reveals the performance came from a surprisingly narrow group of winners.

The iShares Core MSCI Emerging Markets ETF (IEMG) returned a strong +50.4% over the past year, but the median holding among its largest positions gained just +2.7%. That gap tells a story about where your returns actually came from, and it points to a performance driven by a select few rather than a broad market tide.

Photo by ArtsyBee on Pixabay

The Outlier And The Anchor

So, who did the heavy lifting? The single biggest contributor to the fund’s return was Southern Copper (SCCO). Despite making up just 0.1% of the fund, the stock had an outsized positive impact. On the other end of the spectrum, the biggest drag on the fund was Pdd (PDD). It makes up a 0.5% portion of the fund and fell over the past year, weighing on the overall result.

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A Gain Driven By The Few

This dynamic of a few big winners and losers was not an exception. Among the fund’s 14 largest holdings, exactly half rose while the other half fell: 7 rose over the past year and 7 fell. The concentration of the gains is even more stark when you look at the attribution. The five biggest contributors produced about 96% of the combined gains from the holdings measured here. This means that while you own a basket of many stocks, your positive return was overwhelmingly powered by a handful of them.

What This Means For Your Diversification

You buy a fund like IEMG, with its 2658 positions, for diversification across developing global economies. And by count, you have it. But in terms of performance over the last year, the result was highly concentrated. The fund’s success rode on the performance of a very small slice of its portfolio. This isn’t a good or bad thing, but it is a crucial piece of information. It means your investment was, in practice, more sensitive to the fortunes of a few key companies than the long list of holdings might suggest.

Knowing this helps you understand the nature of your holding. The fund’s overall weight concentration is already significant, as its five largest holdings make up 28.8% of the fund. But the return concentration was even tighter. As an owner, the key is to recognize that an index fund’s return is simply the sum of its parts, and sometimes, a few of those parts do almost all the work. Keeping an eye on the fund’s largest single holding, Taiwan Semiconductor Manufacturing (2330.TW) at 12.7% of the fund, is a practical way to stay aware of where your biggest exposure lies.

A Hundred Holdings Is Not Always A Hundred Bets

IEMG’s gains leaned on a handful of names, so your real exposure is more concentrated than the holdings count suggests. The number of holdings tells you far less than where the returns come from, and few ETF buyers ever check the difference. Our ETF Valuation and Performance Scorecard does it across the whole equity universe at once, ranking every fund by risk-adjusted return and showing how top-heavy each one is.

And for the part of a portfolio where you would rather a system handled the spread, the Trefis High Quality (HQ) Portfolio holds 30 individually screened names, re-balanced by rule, with a track record of outpacing a benchmark that combines all major indices – the S&P 500, S&P Mid-cap, and Russell 2000.