Key Takeaways Palantir Technologies and Dell Technologies, along with Erie Indemnity, became members of the S&P 500 Index today.Palantir Technologies shares are trading at all-time highs.Dell's shares were lower in recent trading,

After the index change takes hold, “large-cap funds that are benchmarked against the S&P 500 will be forced to look at” Dell, one analyst says.

A look back at how Tesla stock has performed since being added to the S&P 500 Index as Palantir and Dell join the market index.

Palantir and Dell are joining the S&P 500 Monday along with Erie Indemnity, replacing a trio of stocks that are shifting to some of S&P Global's smaller indexes.

Palantir’s stock has outperformed the S&P 500 by a wide margin in recent years, but Raymond James has concerns about the stock’s valuation.