ImmunityBio's 471% Stock Rally Could Enter Next Round If Shorts Capitulate

ImmunityBio Inc (NASDAQ:IBRX) has already delivered one of 2026's most explosive stock moves. But the conditions behind its 471% year-to-date surge suggest the most volatile phase may still lie ahead.

Source: Benzinga

IBRX stock surged nearly 86% in the past month alone, driven by regulatory momentum and renewed investor focus on its cancer immunotherapy platform. The rally accelerated after regulatory progress tied to its bladder cancer therapy ANKTIVA, which marked ImmunityBio's transition from a development-stage biotech into a commercial oncology company.

But beneath the surface, a powerful positioning imbalance is quietly building.

40% Short Interest Creates A Structural Pressure Point

More than 135 million ImmunityBio shares are currently sold short, representing over 40% of its float. That's an unusually high level — and one that creates structural risk for bearish investors if the stock continues rising.

Short sellers eventually must buy back shares to close positions. When prices rise rapidly, that process can accelerate, forcing additional buying and amplifying upward momentum.

This dynamic has historically driven some of biotech's most explosive multi-phase rallies.

ImmunityBio's small float and extreme price momentum only increase that risk.

Hedge Funds Are Quietly Increasing Exposure

Institutional positioning is also shifting.

Renaissance Technologies, founded by Jim Simons, increased its ImmunityBio stake by over 21% in the fourth quarter. Millennium Management, led by Israel Englander, expanded its position by more than 145% over the same period.

These increases occurred before the stock's most recent surge, suggesting institutional investors were positioning ahead of broader market recognition.

A Classic Repositioning Setup Is Emerging

Biotech rallies driven by regulatory breakthroughs often unfold in stages. Initial gains driven by news are followed by positioning shifts as institutions build exposure and shorts adjust risk.

With extreme short interest, rising institutional ownership, and accelerating momentum, ImmunityBio now has the key ingredients that have historically fueled prolonged squeeze-driven advances.

The first phase may have been driven by regulatory validation.

The next phase could be driven by positioning.

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