United Microelectronics Falls 7%, Tower Semiconductor Sinks 10%, GlobalFoundries Drops 7% as AI Spending Fears Hit Foundries
United Microelectronics, Tower Semiconductor and GlobalFoundries fell sharply as concerns over $3 trillion in off-balance-sheet technology commitments, rising Treasury yields and uncertain AI monetization pressured an extended semiconductor trade.
Foundry stocks sold off Tuesday after The Wall Street Journal reported that nine major technology companies carry roughly $3 trillion in off-balance-sheet commitments, mostly tied to artificial intelligence. The obligations are growing faster than the $600 billion of capital expenditures reported over the past year, raising questions about demand and foundries’ 2027 and 2028 capacity plans. United Microelectronics (NYSE: UMC) fell 7% to $18.22. The shares had gained 153% year to date before the session, giving the company a market capitalization near $45.68 billion and a trailing P/E ratio of 17.71x. The decline appeared to reflect sector-wide de-rating rather than company-specific news. GlobalFoundries (NASDAQ: GFS) dropped 7% to $49.78. Second-quarter 2026 revenue was $1.786 billion, with communications infrastructure and data-center revenue up 62% year over year. The shares remained 53% higher year to date. Tower Semiconductor (NASDAQ: TSEM) sank 10% to $236.10, the largest decline among the group. It reported second-quarter revenue of $460 million, a record 30% gross margin, and third-quarter guidance of $520 million. Management raised its 2028 revenue target to $3.6 billion; the stock was still up 125% year to date. Taiwan Semiconductor Manufacturing (NYSE: TSM) fell 4% to $412.09 but remained 43% higher year to date. Its 32.15x trailing P/E leaves it sensitive to doubts about hyperscaler AI spending and 3nm and 2nm ramps. Anthropic’s annualized revenue run rate reached $65 billion at July’s end, about seven times the prior year, while OpenAI’s reached $40 billion, according to CNBC. Reuters reported Anthropic projects 2028 revenue of $190 billion to $200 billion, underscoring monetization risk. The 30-year Treasury yield exceeded 5.33%, a 19-year high, and traded near 5.29%, raising discount rates for future cash flows. The iShares Semiconductor ETF (NASDAQ: SOXX) fell 6% to $525.68 despite an 86% year-to-date gain. Invesco QQQ Trust (NASDAQ: QQQ) declined 1.66%, indicating broad semiconductor underperformance. Healthcare rose 2% and energy 1%, partly on Middle East oil concerns. Investors should watch whether foundries stabilize or face further pressure as extended gains reverse.