Form 4: Arcellx CEO Sells Shares for Tax Obligations

Arcellx CEO Rami Elghandour reported the sale of 89,916 shares of common stock to cover tax withholding obligations related to RSU vesting, while also disclosing direct and indirect holdings.

Summary

• Rami Elghandour, President, CEO, and Chairman of the Board of Arcellx, Inc., reported changes in his beneficial ownership of common stock.
• The filing indicates a transaction made pursuant to a Rule 10b5-1 plan.
• On February 27, 2026, Mr. Elghandour sold 89,916 shares of Arcellx common stock at a weighted average price of $113.9204 per share.
• This sale was a broker-assisted transaction to satisfy tax withholding obligations in connection with the vesting of restricted stock units (RSUs).
• Prior to this sale, there were acquisitions of common stock on January 2, 2026 (55,459 shares), January 3, 2026 (53,098 shares), and January 6, 2026 (55,991 shares), all at a price of $0, representing RSU vesting.
• Following these transactions, Mr. Elghandour directly beneficially owns 276,051 shares of common stock.
• He also indirectly beneficially owns 198,000 shares through a spousal lifetime access non-grantor trust (spouse as beneficiary) and 218,500 shares through another spousal lifetime access non-grantor trust (reporting person as beneficiary).

Sentiment

Score: 5

Explanation: StockSavvy.ai views this as a neutral event, representing a routine executive compensation-related transaction rather than a strategic move or a reflection of new company performance insights.

Positives

• The vesting of restricted stock units (RSUs) indicates that performance conditions, if any, were met, leading to the executive's equity compensation becoming exercisable.
• The transaction was made pursuant to a Rule 10b5-1 plan, suggesting a pre-arranged sale to avoid accusations of trading on inside information.

Negatives

• The sale of 89,916 shares by a key executive, even for tax purposes, represents a reduction in direct insider ownership.

Future Outlook

NA

Management Comments

• Rami Elghandour serves as President, CEO, and Chairman of the Board of Arcellx, Inc.
• The Reporting Person undertakes to provide upon request by the Commission staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
• The Reporting Person disclaims beneficial ownership except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such shares for Section 16 or any other purpose regarding shares held by trusts.

Industry Context

StockSavvy.ai notes that sales of shares by executives to cover tax withholding obligations upon the vesting of restricted stock units are a common and routine occurrence in the biotechnology and broader public company sectors. These transactions are often pre-scheduled under Rule 10b5-1 plans to manage tax liabilities associated with equity compensation.

Related Party Transactions

• Indirect beneficial ownership of 198,000 shares held by a spousal lifetime access non-grantor trust, of which the Reporting Person's spouse is the beneficiary.
• Indirect beneficial ownership of 218,500 shares held by a spousal lifetime access non-grantor trust, of which the Reporting Person is a beneficiary.
• The Reporting Person disclaims beneficial ownership of these trust-held shares except to the extent of his pecuniary interest.

Stakeholder Impact

• Shareholders: Minimal direct impact as this is a routine tax-related sale, not indicative of a change in company fundamentals or executive confidence beyond the pre-planned nature of the transaction.
• Employees: No direct impact.
• Management: The CEO continues to hold a significant number of shares directly and indirectly, aligning his interests with shareholders.

Key Dates

Recommendation

This Form 4 filing details a routine, pre-planned sale of shares by Arcellx's CEO to cover tax obligations arising from RSU vesting. Such transactions are common and generally do not signal a change in the company's fundamental outlook or the executive's long-term confidence. Therefore, a seasoned investor would likely maintain their current position, as this event does not provide new information warranting a change in investment thesis.

Keywords

Arcellx, ACLX, Form 4, Insider Trading, Stock Sale, Rami Elghandour, Restricted Stock Units, Executive Compensation, Rule 10b5-1