Group 1 - Datadog, a monitoring service provider for servers and databases, will be added to the S&P 500 index, replacing Juniper Networks [1] - Following the announcement, Datadog's stock price surged by 9.64% in after-hours trading [1] - Robinhood's stock experienced a decline of 3.48% in the same trading session [1] Group 2 - Datadog's closing price was reported at 135.01 USD, with an after-hours price of 148.02 USD [4] - The market capitalization of Datadog is approximately 46.63 billion USD [4] - Datadog's 52-week high is 170.08 USD, while the 52-week low is 81.65 USD [4]