On Thursday evening, the index added Arm Holdings, the U.K. chip maker, and dropped Sirius XM Holdings in a move that Barron’s had predicted could happen.
The change, which comes as Sirius’ market value falls below 0.1% of the index’s capitalization, will take place before the start of trading on June 24.
Berkshire Hathaway has stakes in each of these companies, and they could be poised to pop.