Insider Trading January 23, 2026

Amprius Technologies CTO Executes $6.8 Million Share Sale Amid Strategic Company Developments

Stefan Constantin Ionel’s stock transactions coincide with leadership changes and expanded manufacturing capacity at the battery technology firm

By Nina Shah AMPX
Amprius Technologies CTO Executes $6.8 Million Share Sale Amid Strategic Company Developments
AMPX

Amprius Technologies’ Chief Technology Officer, Stefan Constantin Ionel, recently sold over half a million shares totaling around $6.83 million while simultaneously exercising stock options. This activity unfolds during a period of significant stock appreciation and notable company initiatives including a new CEO transition and expanded production partnerships aligned with U.S. regulatory standards.

Key Points

  • Amprius Technologies CTO Stefan Constantin Ionel sold 567,707 shares worth approximately $6.83 million and exercised options for 387,703 shares.
  • The company recently completed an at-the-market offering, raising about $97.5 million by issuing 25.5 million shares, supporting its business expansion.
  • Leadership transition is underway with Tom Stepien becoming CEO in 2026, succeeding Dr. Kang Sun who will remain on the board as an Executive Advisor, signaling a strategic shift.
  • Amprius expanded its Korea Battery Alliance by adding three manufacturers, increasing global contract manufacturing capacity to over 2 GWh, in compliance with U.S. defense regulations.

Stefan Constantin Ionel, serving as Chief Technology Officer at Amprius Technologies, Inc. (NYSE:AMPX), completed the sale of 567,707 shares of the company's common stock, generating roughly $6.83 million in proceeds. These sales were transacted between January 21st and 23rd, with share prices fluctuating narrowly from $12.00 to $12.0365 per share. The trading activity occurs against the backdrop of Amprius's substantial 231% gain in stock price over the past year, although current quotes at $11.17 remain modestly above the fair value estimated by InvestingPro.

In addition to selling shares, Ionel exercised stock options for the acquisition of 387,703 shares on January 21st and 22nd at prices ranging from $0.05 to $0.62 per share, costing him a total of $81,194. This dual action of exercising options and selling equity reflects activity conducted under a pre-established Rule 10b5-1 trading plan initiated by Ionel on September 11, 2025, according to a filed Form 4 with the Securities and Exchange Commission.

Following this series of transactions, Ionel’s direct ownership in Amprius Technologies stands at 748,696 shares. Market analysts retain a positive outlook on AMPX, assigning price targets from $16 to $20, indicating continued potential for share price appreciation from current levels.

Concurrent to these insider transactions, Amprius Technologies has closed an at-the-market equity offering program, netting approximately $97.5 million by issuing around 25.5 million shares. The company is also undergoing significant executive leadership changes; Tom Stepien is slated to assume the role of Chief Executive Officer effective January 1, 2026, succeeding Dr. Kang Sun, who will become an Executive Advisor while maintaining his position on the board of directors. Oppenheimer has sustained its Outperform rating on AMPX, highlighting the CEO transition as a strategic new chapter for the firm.

Moreover, Amprius has strategically broadened its Korea Battery Alliance by incorporating three additional manufacturers. This expansion elevates the organization's global contract manufacturing capacity beyond 2 gigawatt-hours, aligning with compliance objectives dictated by the U.S. National Defense Authorization Act. Additionally, the company finalized amendments to Dr. Sun’s employment agreement detailing his forthcoming compensation and benefits, reinforcing stability during the leadership handover.

These developments collectively reveal Amprius Technologies’ ongoing commitment to strengthening both its management team and manufacturing capabilities in battery technologies. The insider trading activity by the CTO reflects planned, rule-compliant portfolio management amidst a dynamic corporate environment.

Risks

  • Stock price volatility despite significant gains over the past year, with current trading prices slightly above fair value estimates.
  • Potential challenges associated with leadership transitions, including possible strategic or operational uncertainties.
  • Dependence on manufacturing expansion and regulatory compliance may impact operational execution and market positioning.

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