ImmunityBio (IBRX) traded lower as the market revisited regulatory risk tied to the FDA’s warning letter challenging promotional statements about ANKTIVA, keeping a compliance overhang on the shares. The move comes as investors also weigh litigation risk after a securities class action was filed, with shareholder notices highlighting a May 26, 2026 deadline for investors seeking lead-plaintiff status.

Warning letters can extend headline risk beyond the initial selloff because investors price in potential restrictions on marketing, additional remediation steps, and knock-on effects to demand generation efforts. The lawsuit timeline adds another uncertainty layer, raising concern that legal expenses and reputational impact could coincide with ongoing commercial execution needs in a capital-intensive biotech.

Traders are likely to monitor any public updates on remedial actions tied to the FDA’s concerns and whether the company changes promotional language and related communications. In parallel, the lead-plaintiff deadline on May 26, 2026 is a near-term legal milestone that can keep volatility elevated as the case progresses and investors reassess downside scenarios.