Form 4: Y-mAbs CEO Rossi Reports Share Sale Post-Merger

Y-mAbs Therapeutics President & CEO Michael J. Rossi reported the disposition of common stock and conversion of equity awards following the company's acquisition by Stark International Lux.

Summary

• Y-mAbs Therapeutics, Inc. completed its merger on September 16, 2025, becoming an indirect wholly-owned subsidiary of Stark International Lux.
• Michael J. Rossi, President & CEO, reported the disposition of 7,982 shares of common stock at $8.60 per share.
• All outstanding shares of Y-mAbs Therapeutics, Inc. were cancelled in exchange for $8.60 per share in cash.
• Restricted Stock Units (RSUs) and Performance-Based RSUs (PRSUs) held by Mr. Rossi were cancelled and converted into a cash payment equal to the total number of shares issuable multiplied by the $8.60 merger consideration.
• Employee Stock Options held by Mr. Rossi were cancelled and converted into cash equal to the product of the number of shares subject to the option and the excess of the $8.60 merger consideration over the option's exercise price.
• Options with an exercise price equal to or exceeding the $8.60 merger consideration were cancelled for no consideration.

Sentiment

Score: 7

Explanation: The filing reports the successful completion of a merger, resulting in a cash payout for shareholders and the conversion of equity awards for the reporting person. While some options were cancelled for no consideration, the overall event provides liquidity and a defined exit for public shareholders.

Positives

• Shareholders, including the CEO, received a cash payout of $8.60 per share for their common stock.
• Equity awards (RSUs, PRSUs, and in-the-money stock options) were converted into cash, providing liquidity to the reporting person.

Negatives

• Y-mAbs Therapeutics, Inc. is no longer an independent public company, becoming an indirect wholly-owned subsidiary.
• Employee stock options with an exercise price equal to or exceeding the $8.60 merger consideration were cancelled for no consideration, resulting in no value for those specific awards.

Risks

• The risk of stock options being out-of-the-money (exercise price equal to or exceeding the merger consideration) was realized, leading to their cancellation without value.

Future Outlook

The company is now an indirect wholly-owned subsidiary and no longer publicly traded, so no public future outlook is provided in this filing.

Industry Context

This transaction represents a consolidation event within the biotechnology or pharmaceutical industry, where a smaller public company is acquired by a larger entity, often for its pipeline, technology, or market position. Such acquisitions are common strategies for growth and portfolio expansion.

Related Party Transactions

• The transactions reported are those of a key executive (President & CEO) in connection with a corporate merger, which are standard disclosures for insiders.

Stakeholder Impact

• Shareholders: Received $8.60 per share in cash, providing a definitive exit and liquidity.
• Employees (including reporting person): Equity awards were converted to cash, providing liquidity, though some out-of-the-money options were cancelled without value.

Key Dates

Keywords

Y-mAbs Therapeutics, YMAB, Michael J. Rossi, SEC Form 4, merger, acquisition, insider trading, beneficial ownership, common stock, restricted stock units, stock options, tender offer, Stark International Lux