Marvell Technology's stock fell sharply by 5% in pre-market trading on Monday, following its unexpected exclusion from the S&P 500 index. The chipmaker was widely anticipated to join the index after meeting financial eligibility criteria, including reporting positive GAAP earnings.

The disappointment overshadowed recent positive developments, including a 10% rally last week after Marvell announced a $3.25 billion deal to acquire semiconductor startup Celestial AI. Analysts had expected the S&P 500 inclusion to further boost investor confidence, but the snub triggered a sell-off instead.