Shares of Robinhood Markets and Bitcoin asset holding company Strategy declined in after-hours trading following their exclusion from the S&P 500 index. S&P Dow Jones Indices announced that Interactive Brokers Group will join the index, replacing Walgreens Boots Alliance. Robinhood shares fell 0.5% to $107.40 after closing down 1.26% on Monday, while Strategy shares dropped 4.17% and an additional 0.6% to $341 in after-hours trading.