BHP Group and Rio Tinto dropped sharply on June 26, 2026, caught in a wave of selling that started in technology stocks and spread into metals companies. Two separate pressures collided at once: the US dollar strengthened, and investors suddenly questioned how much money tech companies would actually spend building AI data centers, The Wall Street Journal reported.

Here's why the mechanics matter. Industrial metals—copper, lithium, rare earths—are priced globally in dollars. When the dollar rises, miners earn fewer dollars per unit of metal they sell. At the same time, much of mining's recent valuation lift came from the AI story: copper for data-center infrastructure, rare earths for advanced processors. If that spending story weakens, the premium investors were willing to pay for mining shares evaporates too.

The tech selloff had been gathering force across multiple sessions. The Nasdaq fell about 1.61% on June 23, led by AI and semiconductor names, NBC News reported, with weakness spreading into Asian markets. The selling pressure intensified when Federal Reserve commentary suggested interest rates would remain elevated for longer than investors expected, Reuters noted, putting crowded trades in expensive tech stocks under stress.

The Fed signal matters because higher rates change how investors value long-duration cash flows—future earnings streams that won't materialize for years or decades. AI infrastructure buildouts fall squarely into that bucket: nobody yet knows when the spending will produce genuine profits. That same tension surfaced back in late 2025, Reuters reported in November, when AI stocks pulled back sharply as investors demanded clearer timelines for returns on all that capital spending. The June move isn't new stress; it's the same underlying doubt being repriced.

Mining companies face a particularly awkward situation. Their share prices rest on two legs: near-term cash flows from selling iron ore, copper, and energy at current prices, and a forward premium for the AI-driven demand surge. When confidence in that AI surge cracks, both the outlook for commodity prices and the multiple investors will pay for those prices move against you at the same time. That's rare in most market shocks—usually either volumes soften or prices fall, but rarely both.

Currency headwinds add another layer. The US dollar has drifted higher because interest rates in the US have stayed elevated longer than cross-asset traders expected. For miners reporting earnings in dollars but selling output into markets where local end-users determine demand, a stronger dollar is a margin squeeze even when they're shipping the same volume. Natural hedges and long-term contracts help, but equity markets price spot exchange rates (the rates available right now) immediately, regardless of what's locked in on a contract.

None of this means AI-driven demand for copper is fake. Data centers genuinely do consume more copper, and that consumption is growing. But how fast that ramps up, and whether it offsets weakness elsewhere in the industrial economy, is genuinely unclear. Markets appear to be repricing the speed of the trend, not necessarily its endpoint—a distinction that matters for anyone holding mining stocks through volatile interest rate swings.

The past few sessions show how tightly woven tech sentiment and mining equity prices have become. When a Nasdaq decline smaller than 2% moves blue-chip miners with operations spread across continents and multiple metals, it signals a shift in how global stock portfolios move together—one that traditional ideas about sector diversification may not fully account for.