Today’s Market Movers: AMD Hits $1 Trillion and GameStop Surges on CEO Buy

TLDR

• AMD’s market cap crossed $1 trillion for the first time Monday, driven by excitement around Meta’s Muse AI agent, before pulling back Tuesday
• GameStop rose 3.3% in premarket after CEO Ryan Cohen bought 1.15 million additional shares
• AI and chip stocks fell Tuesday as investors took profits after Monday’s record tech rally
• Quest Diagnostics and Labcorp dropped after CMS announced plans to cut Medicare lab reimbursement rates by 15% starting 2027
• Vicor jumped 10% after raising Q3 revenue guidance, citing a new technology licensing deal

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AMD crossed the $1 trillion market cap milestone for the first time on Monday, riding a wave of excitement around Meta’s Muse AI agent. The chip maker then slipped about 1.1% Tuesday as investors pulled back from AI-related stocks after the previous session’s big gains.

Advanced Micro Devices, Inc., AMD

Intel, Marvell, Micron, Corning, Seagate, and Western Digital all fell in premarket trading Tuesday. Coherent and Lumentum also declined as the broader AI and chip sector gave back some of Monday’s gains.

Software stocks moved in the opposite direction. Adobe, Salesforce, ServiceNow, and Workday all rose Tuesday morning, which often happens when chip and memory stocks pull back.

GameStop shares climbed 3.3% in premarket trading. A Form 4 filing revealed that CEO Ryan Cohen purchased 1.15 million additional shares of the company, giving investors a reason to buy.

Lab Stocks Hit After Medicare Announcement

Quest Diagnostics fell 7% and Labcorp dropped 3% after the Centers for Medicare and Medicaid Services said it plans to cut Medicare reimbursement rates for diagnostic tests by 15% starting in 2027.

The cuts are expected to save the federal program around $1 billion per year. CMS noted that Medicare currently pays about 16% more than private health plans for the same tests.

The payment framework had been largely frozen since 2014, which allowed a gap to grow between Medicare rates and private sector pricing. The new cuts aim to bring those rates in line.

Vicor Jumps on Licensing Deal

Vicor surged 10% after raising its third-quarter revenue guidance. The power module company now expects sequential revenue growth of over 20% in Q3, up from its earlier target of around 10%.

The upgrade was driven by royalty fees from a new non-exclusive licensing deal covering its Vertical Power Delivery technology. The deal reinforced investor confidence in the company’s patent portfolio.

Endava shares fell 12% after the company removed its CFO immediately, placing Mark Thurston on administrative leave during an independent accounting investigation. The firm named Conor McShane as interim CFO and brought in advisory firm AlixPartners alongside outside legal counsel.

UBS dropped 3% ahead of a Swiss parliamentary vote on banking capital requirements. CEO Sergio Ermotti warned that forcing the bank to hold up to $20 billion in additional capital could hurt dividends and lending.

Investors are watching whether lawmakers adopt a compromise that allows part of the buffer to be met with Additional Tier 1 debt, or push for stricter hard-equity requirements.

Stock futures were slightly higher early Tuesday, with market attention also turning to preparatory trade talks ahead of a planned U.S.-China bilateral summit.