Mirion Technologies to join S&P SmallCap 600 as GMS is acquired by Home Depot.

Mirion Technologies (MIR) will replace GMS in the S&P SmallCap 600 effective September 9. This change comes after Home Depot (HD) acquired GMS. MIR stock rose over 6% in extended trading. The move reflects the changing landscape in the small-cap index and the impact of M&A activity on index composition.

Title: Mirion Technologies to Replace GMS in S&P SmallCap 600 Effective September 9

Mirion Technologies Inc. (MIR) will replace GMS Inc. (GMS) in the S&P SmallCap 600 index effective September 9, 2025 [1]. This change follows Home Depot Inc. (HD) completing its acquisition of GMS today. The move highlights the dynamic nature of the financial markets and the impact of mergers and acquisitions (M&A) on market indices.

Mirion Technologies, an information technology company, will enter the S&P SmallCap 600 index, while GMS, a distributor of specialty building products, will exit the index [2]. The acquisition of GMS by Home Depot, a component of both the S&P 500 and S&P 100 indices, is a significant factor in this shift. The total enterprise value of the acquisition is approximately $5.5 billion [4].

The S&P SmallCap 600 index is a market-capitalization-weighted index of the 600 smallest companies in the S&P 1500 Composite Index. Index additions typically boost a company's stock as funds tracking the benchmark must purchase shares to maintain accurate representation of the index [3]. Mirion Technologies' stock surged 7% in afterhours trading following the news of its addition to the index.

Home Depot's acquisition of GMS is part of its strategy to increase its share of business with professional contractors. The tender offer for GMS shares expired on September 3, with approximately 79.5% of outstanding shares validly tendered [4]. The Home Depot has accepted these shares for payment at $110 per share in cash.

This change in the S&P SmallCap 600 index underscores the importance of monitoring M&A activity and its impact on market indices. Investors should keep an eye on the performance of both companies to understand the potential implications of this shift.

References:
[1] https://www.prnewswire.com/news-releases/mirion-technologies-set-to-join-sp-smallcap-600-302547135.html
[2] https://www.ainvest.com/news/mirion-technologies-replace-gms-smallcap-600-2509/
[3] https://www.investing.com/news/stock-market-news/mirion-technologies-stock-soars-after-joining-sp-smallcap-600-93CH-4225714
[4] https://www.marketscreener.com/news/the-home-depot-and-its-subsidiary-srs-distribution-complete-acquisition-of-gms-ce7d59d8db8bff24