Form 4: RAPT Director Sells Equity Post-GSK Merger Completion

RAPT Therapeutics director Mary Ann Gray reports the disposition of common stock and stock options following the company's acquisition by GlaxoSmithKline LLC for $58.00 per share.

Summary

• RAPT Therapeutics, Inc. completed its merger with GlaxoSmithKline LLC (GSK) on March 3, 2026, with RAPT becoming an indirect wholly-owned subsidiary of GSK.
• The merger was executed through a tender offer where GSK's subsidiary, Redrose Acquisition Co., acquired all outstanding RAPT common stock for $58.00 per share in cash.
• Director Mary Ann Gray reported the disposition of 4,956 shares of common stock, which were restricted stock units (RSUs) converted into cash at the $58.00 offer price.
• Multiple director stock options were also disposed of; those with an exercise price below $58.00 were cashed out, while those with an exercise price above $58.00 were cancelled for no consideration.
• All outstanding stock options were accelerated and fully vested immediately prior to the merger's effective time.
• A 1-for-8 reverse stock split was effected on June 16, 2025, which adjusted the terms of the stock options.

Sentiment

Score: 7

Explanation: StockSavvy.ai views this as a positive outcome for RAPT shareholders and equity holders with in-the-money options, as the merger completed at a premium, providing liquidity. The cancellation of out-of-the-money options is a standard, albeit negative, aspect of such transactions.

Positives

• The completion of the merger at an Offer Price of $58.00 per share in cash provides a clear liquidity event and return for shareholders and RSU holders.
• Stock options with an exercise price below the $58.00 Offer Price were accelerated, fully vested, and converted into cash, benefiting the option holders.

Negatives

• Stock options with an exercise price greater than the $58.00 Offer Price were cancelled for no consideration, resulting in a loss for those specific option holders.
• RAPT Therapeutics, Inc. ceased to be an independent publicly traded entity, becoming an indirect wholly-owned subsidiary of GSK.

Future Outlook

No forward-looking statements or guidance provided in this Form 4 filing.

Industry Context

StockSavvy.ai notes that this acquisition by GlaxoSmithKline (GSK) of RAPT Therapeutics is consistent with the ongoing trend of larger pharmaceutical companies acquiring smaller biotechnology firms to bolster their pipelines, particularly in areas like immunology and oncology where RAPT had programs. This strategic move allows GSK to integrate RAPT's assets and expertise, potentially accelerating drug development and market entry for new therapies.

Stakeholder Impact

• Shareholders: Received $58.00 per share in cash for their common stock, representing a liquidity event and a premium over pre-merger announcement prices.
• Employees (with equity): Those with in-the-money stock options and RSUs received cash payouts, while those with out-of-the-money options had them cancelled.
• Company (RAPT): Ceased to be an independent public entity, becoming part of GSK, which impacts its strategic direction and operational autonomy.

Key Dates

Keywords

RAPT Therapeutics, GlaxoSmithKline, GSK, Merger, Acquisition, Tender Offer, Form 4, Insider Transaction, Stock Options, Restricted Stock Units, Equity Compensation, Biotechnology, Pharmaceutical