Standard and Poor's Dow Jones Indices said Interactive Brokers will join the S&P 500 Index, replacing Wlagreens' parent company, when trading opens Thursday.

Robinhood Markets shares were slightly lower in extended trading. Some investors have had high hopes that the digital brokerage would be added to the index.

Standard and Poor's Dow Jones Indices said Interactive Brokers will join the S&P 500 Index, replacing Wlagreens' parent company, when trading opens Thursday.