What Happened?
Shares of radiation safety company Mirion (NYSE: MIR) jumped 5.3% in the morning session after the company announced it is set to join the S&P SmallCap 600 index.
The radiation detection systems provider will replace GMS Inc., which was recently acquired by Home Depot, with the change becoming effective before the market opens on Tuesday, September 9. Inclusion in a major stock index is often seen as a positive development because it forces index-tracking funds, such as mutual funds and ETFs, to purchase the company's shares to properly reflect the index's composition. This creates automatic buying pressure.
Is now the time to buy Mirion? Access our full analysis report here, it’s free.
What Is The Market Telling Us
Mirion’s shares are somewhat volatile and have had 13 moves greater than 5% over the last year. In that context, today’s move indicates the market considers this news meaningful but not something that would fundamentally change its perception of the business.
The previous big move we wrote about was 17 days ago when the stock dropped 3.7% on the news that investors took some profits off the table as markets awaited signals on future monetary policy from the Federal Reserve's Jackson Hole symposium later in the week.
The downturn in the market was largely attributed to a significant sell-off in megacap tech and chipmaker shares. Nvidia, Advanced Micro Devices (AMD), and Broadcom all saw notable drops, dragging down the VanEck Semiconductor ETF. Other major tech-related companies like Tesla, Meta Platforms, and Netflix were also under pressure.
A key reason for this trend is that much of the recent market gains have been concentrated in the "AI trade," which includes these large technology and semiconductor companies. So this could also mean that some investors are locking in some gains ahead of more definitive feedback from the Fed.
Mirion is up 32.3% since the beginning of the year, and at $22.39 per share, it is trading close to its 52-week high of $22.42 from July 2025. Investors who bought $1,000 worth of Mirion’s shares 5 years ago would now be looking at an investment worth $2,149.
Unless you’ve been living under a rock, it should be obvious by now that generative AI is going to have a huge impact on how large corporations do business. While Nvidia and AMD are trading close to all-time highs, we prefer a lesser-known (but still profitable) semiconductor stock benefiting from the rise of AI. Click here to access our free report on our favorite semiconductor growth story.
