SAN FRANCISCO (MarketWatch) -- Standard & Poor's late Thursday said that Discover Financial Services /zigman2/quotes/208747867/composite DFS +1.93% will replace ADC Telecommunications Inc. /zigman2/quotes/214411413/composite ADCT -0.82% in the S&P 500, and ADC will replace PH Glatfelter Co. /zigman2/quotes/201799418/composite GLT +1.32% in the S&P MidCap 400 after the close of trading on June 29. Morgan Stanley /zigman2/quotes/209104354/composite MS +1.12% is spinning off Discover in a transaction expected to close by that date. Additionally, S&P said that Covidien Ltd. will replace National Semiconductor Corp. in the S&P 100, and Sanmina-SCI Corp. /zigman2/quotes/207312436/composite SANM -0.08% in the S&P 500. Also, Tyco Electronics Ltd. /zigman2/quotes/205324491/composite TEL +0.27% will replace PMC-Sierra Inc. in the S&P 500, and the new Tyco International Ltd. will replace the pre-spinoff Tyco in the S&P 100 and 500. Tyco is spinning off Covidien Ltd. and Tyco Electronics Ltd. in a transaction expected to close by June 29.