由英伟达、台积电、博通等30家美国上市半导体公司组成的指数，是芯片周期和科技股风险偏好的风向标。
费城半导体指数（SOX）是追踪美国上市的30家主要半导体公司股价的板块指数，成分股包括英伟达、台积电、博通、AMD等，被广泛视为芯片周期和整个科技板块的风向标。
The Philadelphia Semiconductor Index, known as the SOX, tracks 30 U.S.-listed companies engaged in the design, manufacture, and distribution of semiconductors. It was launched in 1993 on the Philadelphia Stock Exchange and is now administered by Nasdaq following its acquisition of the exchange. Members include global chip leaders such as Nvidia, Intel, and TSMC through its U.S. listing. It is the most widely cited equity benchmark for the semiconductor industry.
Because chips go into nearly every modern product, from phones to cars to data centers, the SOX is often read as a leading gauge of global manufacturing and technology demand. The semiconductor industry moves through pronounced boom-and-bust cycles driven by inventories and capital spending, and the SOX is used to judge where the chip cycle stands. Outperformance versus the Nasdaq is frequently taken as a signal that markets expect the chip cycle to improve. The index is highly volatile, so trends usually matter more than day-to-day swings.
The SOX responds to memory and foundry conditions, data-center and AI-related investment, smartphone and PC demand, and geopolitical factors such as U.S.-China technology restrictions. Capital-spending plans and inventory levels reported by major chipmakers can move the index sharply. Asian supply-chain data, such as Korean semiconductor exports and Taiwanese chipmaker revenues, provide useful confirmation of industry conditions. The Nasdaq Composite, global manufacturing PMIs, and earnings from leading chip companies are common cross-checks.