Stock Market Update

[BRIEFING.COM] The major averages have settled into a relatively stable range above their baselines. 

The health care sector (-0.7%) is now the only S&P 500 sector trading lower, weighed down in part by a sharp reversal in Moderna (MRNA 191.35, -11.86, -5.84%), which opened the session with a gain.

Moderna has been volatile in recent weeks as investors weigh upcoming clinical milestones for its oncology pipeline. The stock surged to multi-year highs in late September after the company announced that three abstracts involving its individualized mRNA cancer therapy, intismeran autogene, were accepted for presentation at the ESMO Congress 2026 in October. It subsequently gave back some of that strength after Citigroup downgraded the stock to Sell from Neutral on September 30 and set an $80 target.

The heightened sensitivity reflects the importance of intismeran to Moderna’s oncology strategy. The therapy is being evaluated with Merck's (MRK 140.38, +0.84, +0.61%) KEYTRUDA across several cancer indications, making data timing and efficacy central considerations for investors.