Celcuity, Arista Networks Insiders Lead Wave of Major Stock Sales

A series of substantial stock sales by corporate insiders and major shareholders were reported on Thursday, with transactions at Celcuity and Arista Networks totaling hundreds of millions of dollars. The significant disposals overshadowed a handful of smaller-scale insider purchases reported the same day.

Large Disposals Dominate Activity

The most significant sale by dollar value came from Celcuity Inc., where investment firm Baker Bros. Advisors LP reported the sale of 3.1 million shares on July 14. The transactions, executed at a price of $102.50 per share, amounted to a total of approximately $317.75 million.

Other major sales reported included:

• Arista Networks, Inc.: Shareholder Andreas Bechtolsheim sold 300,000 shares for a total of approximately $54.2 million. The sales were conducted through a family trust under a pre-arranged Rule 10b5-1 trading plan established in February 2026.
• Butterfly Network, Inc.: Director and ten percent owner Jonathan M. Rothberg sold over 4 million shares across three days for a total of $29.4 million. These sales were also made under a Rule 10b5-1 plan, reportedly for estate planning purposes.
• CoreWeave, Inc.: CEO and President Michael N. Intrator sold 307,692 shares for approximately $24.8 million, pursuant to a Rule 10b5-1 plan adopted in November 2025.

Modest Insider Buying Reported

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In contrast to the large-scale selling, reported insider buying was significantly smaller in value. At Boundless Bio, Inc., ten percent owner Kevin Tang purchased 63,969 shares for a total of $155,645 over three days.

Other notable purchases included a $57,366 stock acquisition by Jeffrey A. Goldstein, the Independent Chairman of Fidelity National Information Services, Inc., who elected to receive shares in lieu of a cash retainer. At Cardiff Oncology, Inc., CEO Mani Mohindru acquired 34,364 shares for approximately $50,000.

What This Means for Investors

Tracking insider transactions can provide insight into executive and major shareholder sentiment. Insider buying is often interpreted as a signal of confidence in a company's future prospects. Conversely, insider selling is not always a bearish indicator, as executives may sell shares for personal financial management, diversification, or tax planning.

The prevalence of Rule 10b5-1 plans in Thursday's reported sales is significant. These plans allow insiders to establish a pre-arranged schedule for selling shares at a future date, providing an affirmative defense against accusations of trading on non-public information. This indicates that many of the large sales were planned months in advance and not necessarily a reaction to recent market or company events.