Key Highlights

  • Moderna is set to join the Nasdaq-100 effective October 9, 2026, replacing Warner Bros. Discovery, with shares trading higher in premarket dealings Friday at about $193.15.
  • The stock has more than tripled since mid-August, driven by data from its cancer-treatment programmes, with index-tracking fund buying tied to the inclusion contributing to the latest gains.
  • Warner Bros. Discovery is exiting because of its roughly $110 billion Merger with Paramount Skydance, set to close Tuesday, October 6, with the combined company renamed Skydance under ticker SKYD.
  • Citi analyst Geoff Meacham has a Sell rating on Moderna, believing the rally has stretched the company's valuation beyond what its current pipeline supports.

Moderna (NASDAQ:MRNA) is in the spotlight after Nasdaq announced that the Vaccine and biotech company will join the Nasdaq-100 index, effective October 9, 2026, replacing Warner Bros. Discovery. The announcement capped a remarkable run for Moderna. Its stock has more than tripled since mid-August, driven by data from its cancer-treatment programmes. Shares were trading higher in premarket dealings on Friday at about $193.15.

Why the index Matters

The Nasdaq-100 tracks the largest non-financial companies listed on the Nasdaq exchange. Joining it means Moderna will be added to the portfolios of funds that track the index, including the Invesco QQQ Trust, one of the most heavily traded Exchange-traded funds in the world.

When a stock is added to a major index, those funds must buy its shares to match the new weighting. That often creates a burst of Demand around the effective date, and Moderna's latest gains have been linked to buying tied to the inclusion.

The timing is notable. The Nasdaq-100 closed at a record 30,807.93 on Friday, up 306.37 points, as investors bet a weak jobs report would keep the Federal Reserve from raising rates again in October.

Why Warner Bros. Discovery Is Leaving

Warner Bros. Discovery is exiting because of its roughly $110 billion merger with Paramount Skydance. The deal is scheduled to close on Tuesday, October 6, and the combined company will be named Skydance, trading under the ticker SKYD.

Paramount Skydance chief executive David Ellison said the company will be a creative-first home for bold, quality storytelling. The merged group carries about $80 billion of Debt and has committed to more than 30 theatrical films a year.

Not Everyone Is Convinced

Moderna's surge has divided Wall Street. Citi analyst Geoff Meacham has a Sell rating on the stock, believing the rally has stretched the company's valuation beyond what its current pipeline supports.

Moderna rose to global fame with its Covid-19 vaccine, built on messenger RNA technology. As Pandemic sales faded, the company has been trying to prove that the same platform can work in cancer, rare diseases and other vaccines.

The broader health-care sector was soft on Friday. It was the only S&P 500 sector to fall, by a whisker, as investors poured money into chipmakers and technology. Alnylam, Gilead and Amgen all slipped on the Nasdaq-100.

For index investors, the swap also changes the Nasdaq-100's make-up. Warner Bros. Discovery is a media business, while Moderna adds another biotech to an index already dominated by technology giants such as Nvidia, Apple and Microsoft. Index changes are mechanical decisions based on Market Value and eligibility rules, not endorsements of a company's prospects. Even so, inclusion tends to bring a larger and more stable Shareholder base over time.

October 9 Is the Key Date for Fund Buying

The key date is October 9, when Moderna's inclusion takes effect, so index-tracking funds will need to complete their purchases around then. The Paramount Skydance-Warner Bros. Discovery deal is due to close on October 6. The same week brings the start of third-quarter Earnings season, with PepsiCo on October 8 and Delta on October 9, while the big banks follow on October 13 and 14. Investors will also watch for further oncology data from Moderna, which has driven the stock's recent rally, and the Fed's decision on October 27-28.