Core Insights - Sandisk's shares increased by 7% after being added to the S&P 500 index [1] - The addition follows Sandisk's spin-off from Western Digital, which occurred nine months prior [2] - Sandisk replaces Interpublic in the S&P 500, as Interpublic is being acquired by Omnicom [2] Company Performance - Sandisk's market capitalization is approximately $33 billion following its spin-off [3] - The company reported a 23% revenue increase to $2.31 billion in the latest quarter [4] - There was a 31% increase in exabytes sold during the same period [4] Industry Context - The S&P 500 is increasingly composed of technology companies, particularly in internet, software, and semiconductor sectors [2] - Other recent additions to the S&P 500 include AppLovin, Datadog, DoorDash, and Robinhood [2] - Stocks typically experience a rally upon being added to the S&P 500 due to fund managers needing to purchase shares [3]