Tempus AI Stock Sees Heavy Shorting Amid Cathie Wood’s Ark Invest Selloff — Retail Traders Split On Whether Rally Has Peaked

Short sellers have been increasing their bets against Tempus AI, with short interest hitting a record 25.7% last week, up four percentage points from last week and the highest since the company’s IPO just over a year ago.

The rise in bearish positioning comes as volatility in AI-linked stocks intensifies. Tempus AI’s shares, which hit an all-time high on Sept. 22, fell 19% from those levels by Thursday, ending the five-day period down 11%, according to Ortex data compiled by The Fly. 

The company has been in the spotlight in recent weeks following a string of major announcements. Last month, Tempus AI acquired Paige, a digital pathology firm backed by Memorial Sloan Kettering Cancer Center, for $81.25 million, marking a move CEO Eric Lefkofsky said will accelerate the company’s efforts to build the largest oncology foundation model ever created. 

Paige’s database of nearly 7 million digitized pathology slides is expected to strengthen Tempus’s AI-driven cancer diagnostics platform.

Tempus has also gained recognition from regulatory and government authorities. Earlier this month, it received FDA clearance for its Tempus xR RNA-based diagnostic device and was awarded a $60.57 million contract from the U.S. Department of Health and Human Services to support research initiatives.

Meanwhile, Guggenheim recently raised its price target to $95 from $80, maintaining a ‘Buy’ rating after meeting with company executives to discuss its partnership with AstraZeneca and Pathos AI. The firm described Tempus’s oncology foundation model as “highly differentiated.”

Meanwhile, Cathie Wood’s Ark Invest has been trimming its position in Tempus, selling shares worth more than $10 million over the past three weeks through the ARK Innovation ETF.

On Stocktwits, retail sentiment for Tempus AI was ‘neutral’ amid ‘high’ message volume.

One user said the stock appeared to have experienced a failed breakout and faced a strong rejection last week, adding that it now trades “very choppy” and highlighting $90 as a key resistance level.

Another user dismissed the negative sentiment, suggesting that short sellers were trying to create fear among investors.

Tempus AI’s stock has more than doubled so far in 2025.

For updates and corrections, email newsroom[at]stocktwits[dot]com.

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