Arbuckle Stuart A

Arbuckle Stuart A, EVP and COO, has filed 41 Form 4 transactions across five companies, with a pronounced sell-side bias. Over the observed period, his open-market sales totaled $7.52 million, while he recorded zero open-market purchases. The bulk of his realized sales occurred in Vertex Pharmaceuticals (VRTX) during early 2024, including a $2.14 million sale on February 26, a $2.02 million sale on February 20, and a $1.52 million sale on February 21. A smaller VRTX sale of $29,734 on May 15, 2024, rounded out his direct dispositions. Notably, his most recent four trades—all in 2026—were compensation-related grants (code A) or option exercises (code M) in Rhythm Pharmaceuticals (RYTM), Praxis Precision Medicines (PRAX), and Alnylam Pharmaceuticals (ALNY), each valued at $0, indicating no cash movement. The transaction pattern reveals a clear distinction between discretionary selling and automatic or compensatory activity. Arbuckle’s only open-market sales were concentrated in VRTX in 2024, totaling roughly $5.7 million, while his other VRTX trades were tax-withholding events (code F) that removed shares automatically—collectively valued at over $25 million across 2024 and 2025, including a $16.77 million withholding on July 1, 2025. These F-code transactions are mechanical, tied to vesting or option exercises, and do not reflect a discretionary decision to exit. His recent activity in RYTM, PRAX, and ALNY consists entirely of zero-value grants and exercises, suggesting ongoing equity compensation rather than active portfolio management. Across all 41 filings, Arbuckle has never executed a single open-market purchase, underscoring a persistent one-way flow of shares out of his holdings. The absence of P-code buys, combined with the heavy F-code withholdings and the 2024 VRTX sales, points to a consistent pattern of monetizing equity awards rather than accumulating additional stock. His current positions in RYTM, PRAX, and ALNY appear to be newly established through compensation, but no recent sales in those tickers have been reported, leaving his sell activity firmly anchored in VRTX.