Why did PLTR move on Dec 13, 2024?

On December 13, 2024, after the market closed, Nasdaq officially announced the results of its annual reconstitution of the Nasdaq-100 Index. Palantir (PLTR) was named as one of the three high-profile additions to the index, alongside MicroStrategy and Axon Enterprise, with the changes set to take effect on December 23, 2024. This highly anticipated index inclusion served as the primary catalyst for the stock's positive momentum, as it forces passive index-tracking funds and ETFs to purchase billions of dollars worth of PLTR shares.