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, while Erie's rose.

Palantir Technologies (PLTR) and Dell Technologies (DELL) moved in different directions Monday as they joined the benchmark S&P 500 Index. Shares of Palantir rose, while Dell's edged lower.

That’s in contrast to Sept. 9, the first day of trading after S&P Global announced their additions to the index, along with insurer Erie Indemnity (ERIE). All three got a boost then; Erie shares are up about 1.5% today.

Companies can see their stocks get a lift when they’re added to a major index like the S&P 500. Inclusion exposes them to a wider group of investors who could become aware of a company through an index, while the stocks can also be added to various index funds that track stocks which are added to the measures.

With today’s advance, shares of Palantir Technologies are trading at all-time highs. Shares of Dell and Eric are trading higher this year.

American Airlines (AAL), Etsy (ETSY) and Bio-Rad (BIO) left the S&P 500 as part of the latest changes. All three companies' stocks were recently lower.

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