Shares of Robinhood Markets (HOOD) are surging 5.01% in intraday trading on Friday, as investors continue to bet on the online brokerage's potential inclusion in the S&P 500 index. This marks the sixth consecutive day of outperformance for the stock, which has been rallying ahead of tonight's expected S&P 500 rebalance announcement.

Robinhood, with its market capitalization of approximately $63 billion, is among the top candidates for potential addition to the prestigious index. According to a Barron's report, Robinhood is one of the largest U.S.-domiciled companies not currently in the S&P 500. The announcement of any changes to the index components is anticipated around 5:15 p.m. ET today, with any additions likely to take effect before the start of trading on Monday, June 23.

The potential inclusion in the S&P 500 is highly coveted by companies due to the prestige it brings and the increased demand from index funds, which typically own more than a quarter of the stocks in the index. This explains the recent surge in Robinhood's stock price, as investors position themselves ahead of the possible announcement. It's worth noting that stocks often rise on news of addition to the S&P 500 and in the run-up to inclusion.