Philadelphia Semiconductor Index surges 3.5% as chip stocks rally

A broad-based rally swept across the semiconductor sector Monday, with the Philadelphia Semiconductor Index surging more than 3.5%, as investors piled into chip stocks on sustained optimism around artificial intelligence spending.

"The AI infrastructure buildout continues to drive demand across the entire semiconductor value chain," according to a July 5 analysis on Seeking Alpha. "If semis are to add to gains in the second half, AI will need to keep driving growth forward."

Advanced Micro Devices Inc. and Broadcom Inc. led the charge, each gaining more than 6%. Intel Corp. and Qualcomm Inc. rose more than 5%, while Taiwan Semiconductor Manufacturing Co. added nearly 5%. ASML Holding NV and Marvell Technology Inc. climbed more than 3%, and Micron Technology Inc. advanced nearly 3%.

The rally comes after the semiconductor sector posted a powerful second-quarter performance, recovering from a late-first-quarter pullback. The SOX index, which tracks 30 of the largest US-listed semiconductor companies, has been driven primarily by AI-related demand for advanced chips used in data center training and inference workloads. The question for the second half is whether AI spending can sustain the momentum — or whether valuations have already priced in the growth.

The breadth of Monday's rally — with gains across design, manufacturing, and equipment stocks — suggests the move was driven by broad sector optimism rather than company-specific catalysts. AMD and Broadcom, both heavily exposed to AI data center chips, posted the largest percentage gains. AMD's MI300 series accelerators compete directly with Nvidia Corp.'s H100 and Blackwell GPUs in the AI training market, while Broadcom's custom ASIC business has secured major wins including a five-year deal with Apple Inc.

Intel and Qualcomm, which have been expanding their AI chip portfolios, each rose more than 5%. Intel's Gaudi 3 accelerator targets the AI inference market, while Qualcomm's Snapdragon X series brings on-device AI capabilities to the PC market. TSMC, the world's largest contract chipmaker and a key supplier to both AMD and Nvidia, added nearly 5%. The company's advanced packaging capacity, particularly its CoWoS technology, remains a critical bottleneck in the AI supply chain.

ASML, the Dutch lithography equipment maker that holds a near-monopoly on extreme ultraviolet machines needed for advanced node production, gained more than 3%. Marvell Technology, which provides custom silicon and data infrastructure solutions, also rose more than 3%. Micron Technology, the largest US memory chipmaker, advanced nearly 3% — a move that comes as Samsung Electronics plans to raise DRAM prices by 20% in the third quarter, according to a report.

The semiconductor sector's valuation remains elevated after the second-quarter run. The iShares Semiconductor ETF (SOXX) trades at multiples above historical averages, reflecting the market's expectation that AI-driven demand will continue to outpace cyclical headwinds in automotive and industrial chips. Investors are watching Nvidia's upcoming earnings for confirmation that AI chip demand remains on track, and any signs of slowing in hyperscaler capital expenditure could trigger a sector-wide pullback.

This article is for informational purposes only and does not constitute investment advice.