MP Materials Just Sank 21% in a Month. Is It Time to Sell, or Is This a Prime Buying Opportunity?

Rare earth stocks just shed a fifth of their value while the broad market barely budged, leaving MP Materials shareholders facing a decision that the numbers alone cannot resolve.

Published September 28, 2026, 3:23pm ET · 3 min read

Market Movers desk. Editor: David Moadel.

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Rare earth stocks just had a rough month, and MP Materials (NYSE:MP) sits right in the middle of the damage. MP Materials stock is at $46.75, down 21% over the past month. That slip raises a fair question about whether the drop reflects the mine or the mood surrounding the whole group.

The VanEck Rare Earth and Strategic Metals ETF (NYSEARCA:REMX) is down 17% over that period, a sharp decline for a diversified sector basket. Meanwhile, the SPDR S&P 500 ETF Trust (NYSEARCA:SPY) is up 0.1% over that span, leaving stocks essentially where they began. One corner of the market got repriced while the broad market held up.

Across the domestic critical minerals group, USA Rare Earth (NASDAQ:USAR) stock is at $14.63, down 23% over the past month. United States Antimony (NYSEAMERICAN:UAMY) stock fared better at $4.32, down 15% across the same window. Every name in the strategic metals group lost ground, which points to a theme being sold wholesale.

MP Materials Gave Up a Fifth of Its Value

The recent moves in MP stock may be surprising since there’s been positive news for the company. Specifically, MP Materials is reportedly expected to ship its first magnets to General Motors (NYSE:GM | GM Price Prediction) in the fourth quarter, produced at its Fort Worth, Texas facility.

Nevertheless, MP Materials stock lost value in a month when the stock market ended up close to where it started, and that gap sits at the heart of the story. A decline spread this equally across companies with distinct metals, separate mines and different customers suggests investors are selling the theme itself. The pressure landed on the group as a whole, and the sector’s largest name absorbed its share.

How Rival Names and the Sector Fund Stacked Up

MP Materials stock landed in the middle of the pack. USA Rare Earth stock dropped further, while United States Antimony shares slipped less, placing MP Materials right inside the range set by its smaller peers. Such an ordering across three separate businesses hints at a shared driver.

A gap between the rare earths group and the S&P 500 fund tells the clearest part of the story. Strategic metals names slip hard while the broad index finished nearly steady, a pattern consistent with a theme losing its premium. Against that background, MP Materials stock simply rode the current lower alongside its peers.

Weighing the Case for Selling Against Holding

Shareholders leaning toward selling have a coherent argument. A group-wide unwind against a flat market usually means the premium attached to a theme is being withdrawn, and a stock repriced that way tends to keep falling until something specific to MP Materials stops the slide.

MP stockholders have their own case. MP Materials stock slipped without any company-specific failure, the entire complex moved together, and the assets that made MP Materials the largest name in the group are unchanged by a month of selling.

What the Month Means for Your Portfolio

The month leaves MP Materials shareholders with a judgment call that the figures alone can’t make. Anyone holding MP stock should size their positions so that another leg lower in the rare earths group wouldn’t force a decision under pressure.

Whether this stretch marks the start of a longer unwind or a brief sector-wide reset, MP Materials shareholders need to align their allocation to the group with their tolerance for sharp swings. The next development specific to MP Materials may be what finally separates the company from the pack.

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David Moadel

David Moadel is financial writer specializing in stocks, ETFs, options, precious metals, and Bitcoin. David has written well over 1,000 articles for leading online publications, helping investors understand markets, income strategies, and risk.His work has appeared in The Motley Fool, InvestorPlace, U.S. News & World Report, TipRanks, ValueWalk, Benzinga, Market Realist, TalkMarkets, Finmasters, 24/7 Wall St., and others.With a master’s degree in education, David has taught at the elementary, high school, and college levels. That teaching background shapes his writing style: clear, educational, and practical. David has also built a loyal social-media audience by providing trustworthy financial content on YouTube, X/Twitter, and StockTwits.

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