Sept 6 (Reuters) - The S&P Dow Jones Indices said on Friday server maker Dell Technologies DELL.N, data analytics firm Palantir Technologies PLTR.N and property and casualty insurer Erie Indemnity ERIE.O will join the benchmark S&P 500 .SPX before the market opens on Sept. 23.
Shares of Palantir rose 8% in extended trading, while those of Dell and Erie rose 6% and 3%, respectively.
The three companies will replace American Airlines Group AAL.O, online marketplace Etsy ETSY.O and diagnostics company Bio-Rad Laboratories BIO.N in the index.
Shares of American Airlines were down 0.7%, while those of Bio-Rad Laboratories and Etsy fell about 1%.
(Reporting by Zaheer Kachwala in Bengaluru; Editing by Shinjini Ganguli)