Street Calls of the Week
Investing.com -- Mirion Technologies Inc (NYSE:MIR) stock surged 7% in afterhours trading following news that the company will be added to the S&P SmallCap 600 index.
The radiation detection and measurement solutions provider will replace GMS Inc (NYSE:GMS) in the index effective prior to the opening of trading on Tuesday, September 9, 2025. The change comes after Home Depot Inc (NYSE:HD), a component of both the S&P 500 and S&P 100 indices, completed its acquisition of GMS today.
Index additions typically boost a company’s stock as funds tracking the benchmark must purchase shares to maintain accurate representation of the index. The S&P SmallCap 600 is widely followed by institutional investors and index funds.
Mirion Technologies , which operates in the Information Technology sector according to S&P Dow Jones Indices’ classification, will join the small-cap index as GMS exits from the Industrials sector.
The index change will be implemented before markets open on September 9, giving investors and fund managers time to prepare for the adjustment to their portfolios.
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