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- Weekly Wrap Up: Sunday 12/21/25
Weekly Wrap Up: Sunday 12/21/25
Activ8 News Team
December 21, 2025
Another week, another reminder that activist short selling remains one of the market's most unpredictable forces. While The Economist spent the week interviewing America's most prominent short sellers about where they're placing their bets, three new reports landed on very different corners of the market. From a 50-year-old radiology chain rebranding itself as an AI juggernaut, to a transit contractor accused of masquerading as a software platform, to sidewalk delivery robots facing existential questions about their business model. The market's reaction? Counterintuitive as ever. Two stocks that faced serious fraud allegations actually rallied by week's end, while the company with the mildest critique barely moved. As Jim Chanos quipped to The Economist, "We've got to the 'data-centres-in-space' stage of the cycle."
This Week's New Reports
- Hunterbrook Media targets RadNet (RDNT), alleging the radiology chain's AI rebranding masks a business where Digital Health generates less than 5% of revenue. Stock rallied +5.6% for the week despite serious allegations.
- Bleecker Street Research exposes Via Transportation (VIA) as a labor-intensive transit contractor disguised as a SaaS platform, with 72% of revenue from services and top customers defecting. Stock surged +14.0% for the week.
- The Bear Cave questions Serve Robotics (SERV) economics: $80M loss on just $2M revenue, vandalism issues, and public backlash. Stock gained +7.4% for the week.
- All three reports featured companies trading at aggressive valuations despite fundamental business model concerns raised by researchers.
New Activist Reports
NASDAQ • Hunterbrook MediaDecember 16, 2025
| Metric | Price | Change |
| Close (Day Before) | $72.58 | — |
| Low (Report Date) | $64.75 | -10.8% |
| Close (Report Date) | $71.22 | -1.9% |
| Close (End of Week) | $76.68 | +5.6% |
Stock Price Impact:
RadNet experienced significant intraday volatility following Hunterbrook's release, plunging as much as 10.8% to a low of $64.75 before recovering to close down just 1.9% on the report date. By week's end, the stock had not only recovered but rallied to $76.68, representing a 5.6% gain. This counterintuitive response suggests either the market had already partially priced in concerns, or investors view the AI rebranding narrative as more durable than the short thesis implies. The resilience mirrors a broader pattern where detailed short reports on companies with strong momentum often struggle to sustain downward pressure.
About RadNet:
RadNet is a nearly 50-year-old outpatient imaging company operating over 400 diagnostic imaging centers across eight states. Founded by CEO Dr. Howard Berger in the early 1980s and headquartered in California, the company has recently repositioned itself as an AI healthcare technology play through its Digital Health division. RadNet trades on NASDAQ with a market cap of approximately $6 billion, roughly 3x annual revenue. The company acquired DeepHealth and iCAD to bolster its AI capabilities, though critics question whether these acquisitions justify the premium valuation.
Key Points from the Report:
- Digital Health generates less than 5% of total revenue (~$65M out of $1.5B in the first 9 months of 2025)
- Approximately half of Digital Health sales are internal, sold to RadNet's own imaging centers
- Same-center sales growth allegedly inflated: Hunterbrook estimates ~57% came from closing nearby centers and shifting patients
- Real organic growth may be only 2.5-3%, not the reported 6-10%
- The 2024 10-K contained three different revenue figures for the Imaging Center business ($1.83B, $1.763B, $1.792B)
- Insiders sold $50.9 million in stock over two years with zero open-market purchases
- CFO Mark Stolper sold 35,000 shares (roughly one-third of holdings) in September 2024
- Company pays $180,000/year to rent a New York apartment for a trust set up for the CEO's children
- Competitors view RadNet as "predatory" and won't buy their AI products; SimonMed switched to competitor Lunit after iCAD acquisition
NYSE • Bleecker Street ResearchDecember 16, 2025
| Metric | Price | Change |
| Close (Day Before) | $29.31 | — |
| Low (Report Date) | $29.00 | -1.1% |
| Close (Report Date) | $30.18 | +3.0% |
| Close (End of Week) | $33.41 | +14.0% |
Stock Price Impact:
Despite Bleecker Street's detailed 60% downside thesis, Via Transportation's stock showed remarkable resilience, dipping only briefly to $29.00 before closing higher on the report date. By week's end, shares had surged 14% to $33.41, moving decisively in the opposite direction of the $11.80 price target. This represents one of the more dramatic "short squeeze" style reactions of 2025, suggesting either strong institutional support or that the recent IPO's momentum proved more powerful than the bear case. The complete reversal illustrates why activist short selling remains one of the riskiest strategies in the market.
About Via Transportation:
Via Transportation is a New York-based public transit technology company that recently went public on the NYSE with a market cap of approximately $2.4 billion. The company provides microtransit and paratransit services, marketing itself as a software-as-a-service (SaaS) platform for transit agencies. Via partners with cities and transit agencies to provide on-demand transportation solutions, though critics contend the business model is more labor-intensive contractor than technology platform. The company faces a potential "fiscal cliff" in 2026 as COVID-era transit funding expires.
Key Points from the Report:
- Approximately 72% of revenue comes from services (driver hours, vehicle utilization), not software
- Software fees typically represent less than 5% of total contract value per reviewed agreements
- Bleecker Street's price target: $11.80 (representing 60% downside based on 2.2x 2027E gross profit)
- LA Metro forced a 15% price cut, split the contract, and gave software to competitor Spare Labs
- Minneapolis Met Council replaced VIA software with Spare Labs in October 2024
- Arlington, Texas cut its $30.2M contract by 31% to $20.8M, with 96% being services
- Hillsborough County, FL terminated VIA paratransit software due to "inability to meet required functionality"
- Adjusted service margin is only ~22% after including insurance and support costs
- COVID-era grant funding expiring in 2026 creates significant fiscal cliff risk
NASDAQ • The Bear CaveDecember 18, 2025
| Metric | Price | Change |
| Close (Day Before) | $9.55 | — |
| Low (Report Date) | $9.93 | +4.0% |
| Close (Report Date) | $10.12 | +6.0% |
| Close (End of Week) | $10.26 | +7.4% |
Stock Price Impact:
Notably, Serve Robotics never traded below its pre-report close following The Bear Cave's publication. The stock actually opened higher and continued climbing, finishing the week up 7.4%. This unusual response may reflect that The Bear Cave's analysis focused more on fundamental business model questions rather than allegations of fraud or misconduct. With the robotics delivery space attracting significant speculative interest, investors appear willing to overlook the staggering 40:1 loss-to-revenue ratio in favor of long-term optionality on the autonomous delivery thesis.
About Serve Robotics:
Serve Robotics is an autonomous sidewalk delivery robot company that spun out of Postmates in 2020 following Uber's acquisition of the food delivery platform. The company went public via reverse merger in April 2024 and currently trades on NASDAQ with a market cap of approximately $711 million. Serve partners with Uber Eats and DoorDash to provide last-mile delivery services using its fleet of sidewalk robots. The company is headquartered in the United States and represents one of several startups competing in the autonomous delivery space alongside Starship, Nuro, Avride, and Coco Robotics.
Key Points from the Report:
- Company lost approximately $80 million on just $2 million in revenue over the last twelve months (40:1 loss-to-revenue ratio)
- Robots face regular vandalism and theft incidents documented on social media accounts like @FilmTheRobotsLA
- Viral video showed a Serve robot awkwardly forcing its way through restaurant sidewalk seating in Miami
- Entrepreneur Nikhil Krishnan noted: "People just don't like dealing with them, they bully them, and they're slow"
- Faces intense competition from Starship, Nuro, Avride, and Coco Robotics
- Industry observers question whether sidewalk robots are the right form factor versus autonomous cars or drones
- Listed via reverse merger in April 2024, bypassing traditional IPO due diligence
- Average daily trading volume of approximately $100 million suggests significant speculative interest
Activ8 Newswire
Recent articles and news from around the activist short selling world
Where America's Most Prominent Short Sellers Are Placing Their Bets
The Economist interviews three prominent financial sleuths about their current market views. Jim Chanos delivers a memorable quip about AI hype: "We've got to the 'data-centres-in-space' stage of the cycle." The feature explores where veteran short sellers see opportunity as valuations remain stretched.
Source: The Economist
When a Short Report Lands, Banks Can Hike Up Interest on New Loans
New research from HEC Paris examines the ripple effects of activist short reports beyond stock prices. When companies become targets, banks often respond by increasing interest rates on new loans, adding another layer of financial pressure that compounds the challenges faced by targeted companies.
Source: Forbes / HEC Paris
One of Germany's Most Popular Short Bets Is Getting Even More Crowded
Bloomberg follows the intensifying short attack on Gerresheimer, a German pharmaceutical packaging company targeted by Morpheus Research. The Hindenburg-linked research firm alleges accounting irregularities and questions the company's CagriSema-driven growth narrative. Germany's financial regulator BaFin has announced a formal audit.
Source: Bloomberg
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