Moderna joins the Nasdaq-100, replacing Warner Bros. Discovery
Oct 12, 2026
Moderna (NASDAQ: MRNA) joined the Nasdaq-100 index before the market opened on Friday, October 9, 2026, replacing Warner Bros. Discovery. Nasdaq announced the change on October 1. Moderna shares closed higher on October 9, their first day as a member of the index.
Why the change was made
Warner Bros. Discovery left the Nasdaq-100 after the completion of its acquisition by Paramount Skydance on October 6. Following the merger, the combined company is called Skydance Corporation and its shares are listed on the New York Stock Exchange. When a company leaves the Nasdaq-100 because of an acquisition, Nasdaq selects a replacement based on the index rules.
About the Nasdaq-100
The Nasdaq-100 includes 100 of the largest non-financial companies listed on the Nasdaq stock market. It is weighted by market capitalisation, so larger companies have a bigger effect on the index. According to Nasdaq, more than 200 investment products, with over $800 billion in assets under management globally, track the index.
The index is reviewed once a year in December, but changes can also be made during the year when a company is removed, for example after a merger or acquisition.
What index inclusion means
When a company joins an index, funds that track it, such as exchange-traded funds (ETFs), typically need to buy its shares so that their holdings match the index. This can increase trading volumes around the date of the change. Index inclusion does not change a company's business, revenue or profit, and its effect on the share price can be temporary.
Index changes are usually announced several days before they take effect, as in this case. This gives index funds time to prepare, and some of the related trading can take place before the effective date.
Other index changes linked to the merger
Warner Bros. Discovery is also being removed from other major indices following the completion of the merger. According to Reuters, these include indices run by MSCI and S&P Dow Jones Indices. Each index provider selects replacements according to its own rules.
Moderna's share performance
According to Reuters, Moderna shares have risen more than sixfold this year, giving the company a market value of about $75 billion before the index change. Reported moves on October 9 differ by source and time of day. Market reports also linked trading on the day to a New York Times report about a public-private effort to speed up the development of cancer vaccines. Past share price performance does not indicate future performance.
About Moderna
Moderna, based in Cambridge, Massachusetts, develops medicines and vaccines based on messenger RNA (mRNA) technology. It became widely known for its COVID-19 vaccine. The company is also developing vaccines for other respiratory viruses and individualised cancer treatments, some of which are still in clinical trials.
Analyst views
Analyst opinions on Moderna differ. Some analysts have raised concerns about the stock's valuation after this year's rise, while others focus on the company's pipeline. These are third-party opinions, not company guidance.
Risks and uncertainties
Moderna's future performance depends on factors including the results of clinical trials, regulatory approvals, vaccine demand, competition, pricing and costs. Many of its pipeline products are not yet approved and may not reach the market. Biotech shares can be highly volatile, particularly after large price moves. Index inclusion can be followed by reduced buying once funds have adjusted their holdings.
What this means for investors
For Investing.one users following MRNA, the stock is now part of one of the most widely tracked US stock market indices. Index membership is reviewed regularly and can change.
Sources
This is not investment advice. Your capital is at risk. Past performance does not guarantee future returns.
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