Astera Labs stock rose 9.5% in morning trading today, reaching $396.82 and hitting an intraday high of $400.73. Traders positioned around expectations that the AI connectivity chipmaker will join the S&P 500 Index during its next quarterly rebalancing.

Passive investment vehicles account for roughly 30% of assets tracking the S&P 500. Funds that replicate the benchmark must buy shares of any new member, which often creates upward price movement before an official announcement.

Analysts have identified Astera Labs as a leading candidate for index admission. The company meets all key eligibility requirements. Its market capitalization stands near $47.6 billion, well above the S&P 500's current minimum threshold of $22.7 billion.

Fubon recently initiated coverage of Astera Labs with a Buy rating and a $500 price target. The firm joins other analysts who have upgraded their outlook on the stock in recent weeks.