MP Materials Corp. (MP) saw its stock price plummet 5.11% during intraday trading on Monday. The rare earths producer experienced significant selling pressure early in the session.

The decline follows news that Hancock Prospecting, a major shareholder, has diversified its U.S. portfolio. Recent filings show Hancock took a 6.3% stake in competitor Rare Earths Americas (REA) in the current quarter, while maintaining MP Materials as one of its core holdings. This move by a significant investor into a competing rare earths company may have raised concerns about MP's competitive positioning.

Adding to the sentiment, a separate industry analysis published intraday highlighted the evolving competitive landscape for rare earth mining. The report noted the emergence of new projects and quoted MP's own CEO emphasizing the rarity of "economic orebodies." The article also featured commentary from REA's CEO discussing the substantial new mine capacity required to meet future demand, particularly from the AI and robotics sectors, underscoring the potential for increased competition in the space.