Group 1 - Block Inc. will join the S&P 500 index, replacing Hess, effective before the opening bell on July 23, 2025, leading to an 8.5% increase in its shares during extended trading on July 18, 2025 [1] - The S&P 500 index saw recent changes, with The Trade Desk replacing Ansys, and Hess exiting due to Chevron's $54 billion acquisition [2] - Companies added to the S&P 500 typically experience stock price boosts due to fund managers and index-tracking ETFs rebalancing their holdings [3] Group 2 - Block's addition enhances the tech presence in the S&P 500, as the company, originally known as Square, has diversified into various financial services and rebranded to Block in 2021 to emphasize its commitment to blockchain technologies [4] - Despite a 16% year-to-date decline, Block's stock has surged 14.5% over the past month, with a market capitalization of approximately $45 billion, positioning it above the median company in the index [5] - Several ETFs, including Twin Oak Endure ETF (SPYA) and VanEck Digital Transformation ETF (DAPP), have significant investments in Block, with SPYA allocating about 7% of its weight to Block shares [6]