Welcome to our dedicated page for Amprius Tech SEC filings (Ticker: AMPX), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
This page provides access to U.S. SEC filings for Amprius Technologies, Inc. (NYSE: AMPX), a manufacturer of high-energy and high-power lithium-ion batteries based on a Silicon Anode Platform. These regulatory documents offer detailed insight into the company’s operations, capital structure, executive changes, and financing activities.
Amprius uses current reports on Form 8-K to disclose material events. Recent 8-K filings describe the completion of an at-the-market equity offering program established under an At Market Issuance Sales Agreement, including the aggregate offering size and the resulting net proceeds. Other 8-Ks outline leadership transitions, such as the planned change in Chief Executive Officer, the appointment of a new Chief Financial Officer, and related employment and consulting arrangements, including salary, bonus eligibility, equity awards, and severance terms.
Investors and analysts can also use Amprius’ SEC filings to follow its periodic financial reporting. The company has filed 8-Ks to announce quarterly business and financial results and to furnish letters to shareholders discussing results for specific quarters. These filings complement the company’s earnings press releases and conference calls by providing formal disclosure under SEC rules.
On Stock Titan, AI-powered tools summarize lengthy filings so readers can quickly understand the key points in Amprius’ 10-K annual reports, 10-Q quarterly reports, and 8-K current reports, without needing to parse every technical detail. The platform also surfaces information related to equity compensation, executive employment agreements, and capital-raising activities. Real-time updates from EDGAR ensure that new filings, including any future Forms 4 reporting insider transactions, become available promptly with plain-language explanations to help users interpret their significance.
Amprius Technologies, Inc. disclosed that a director and officer serving as President received an equity award in the form of restricted stock units. On December 19, 2025, the reporting person acquired 200,000 shares of common stock at a price of $0, as noted in a footnote describing these shares as restricted stock units granted on that date, with a vesting commencement date of January 1, 2026.
Each restricted stock unit represents the right to receive one share of Amprius common stock. One quarter of the award will vest on February 20, 2027, and the remaining units will vest in equal quarterly installments over the following three years on May 20, August 20, November 20 and February 20, until fully vested on February 20, 2030, subject to continued service. After this transaction, the reporting person beneficially owns 610,000 shares, including 600,000 restricted stock units subject to their respective vesting schedules and conditions.
Amprius Technologies announced a leadership transition. Chief Executive Officer Dr. Kang Sun told the board he will step down from his officer role effective December 31, 2025, and become Executive Advisor on January 1, 2026, while remaining on the board. The company states his decision is not due to any disagreement over operations, policies, or practices.
Amprius entered into a new employment agreement with Dr. Sun, giving him a $633,000 annual salary without bonus eligibility and providing six months of salary continuation and partial accelerated equity vesting if he is terminated without cause, resigns for good reason, or upon death or disability, with full stock option vesting if this occurs in connection with a change in control. Current President Tom Stepien has been appointed Chief Executive Officer effective January 1, 2026, with a $633,000 base salary, a target annual cash bonus equal to 100% of salary, and a grant of 200,000 restricted stock units that vest over four years.
Amprius Technologies’ Chief Technology Officer reported option exercises and share sales in December. On 12/11/2025, he exercised stock options for 125,000 shares of common stock at an exercise price of $0.05 per share, increasing his direct holdings.
On the same date, he sold 198,255 shares of common stock at an average price of $10.5086 per share, with individual trade prices ranging from $10.14 to $11.49. After these transactions, he directly held 748,696 shares, which includes 585,697 restricted stock units that vest over time, and 310,962 stock options remained outstanding. The exercises and sales were carried out under a Rule 10b5-1 trading plan adopted on September 11, 2025.
A shareholder has filed to sell common stock under Rule 144. The notice covers a proposed sale of 198,255 common shares through Morgan Stanley Smith Barney LLC on the NYSE, with an aggregate market value of $2,188,735.20 and 130,483,838 shares of the class outstanding.
The shares to be sold come from recent and prior equity awards, including 125,000 shares acquired on December 11, 2025 through a stock option exercise for cash, 43,464 shares from restricted stock units granted on May 20, 2024, and 29,791 shares from stock options previously exercised on December 14, 2022. In the past three months, the seller, Stefan Constantin Ionel, already sold 25,024 common shares on November 21, 2025 for gross proceeds of $252,274.45.
Amprius Technologies, Inc. insider transaction: the company’s Chief Technology Officer, Constantin Ionel Stefan, reported the sale of 25,024 shares of Amprius common stock on 11/21/2025 at an average price of $10.0813 per share, according to a Form 4 filing. The transaction is coded as a sale and was carried out under a non-discretionary sell-to-cover arrangement mandated by the company to fund tax withholding obligations tied to the vesting of restricted stock units, meaning the sale was made to cover taxes rather than as an open-market discretionary sale. After this transaction, Stefan beneficially owns 821,951 shares of Amprius common stock, which includes 585,697 restricted stock units that each represent a right to receive one share of common stock if their vesting conditions are met.
Amprius Technologies (AMPX) CEO Kang Sun reported an automatic sale of company stock. On 11/21/2025, he disposed of 68,655 shares of Amprius common stock at an average price of $10.0813 per share in a transaction coded "S." The sale was carried out under a non-discretionary, sell-to-cover arrangement mandated by the company to fund tax withholding obligations tied to the vesting of restricted stock units, meaning the sale was for tax purposes rather than an open-market portfolio decision.
Following this transaction, Kang Sun beneficially owned 1,403,651 shares directly, which include 1,285,576 restricted stock units that may convert into common shares if vesting conditions are met. He also indirectly held 274,275 shares through the KANG & CECILLIA SUN FAMILY REVOCABLE TRUST, where he and his spouse serve as co-trustees.
AMPX filed a notice under Rule 144 for a planned sale of company stock by an affiliate. The filing covers the proposed sale of 68,655 shares of common stock through broker Morgan Stanley Smith Barney LLC on the NYSE, with an indicated aggregate market value of 692,132. The company’s common shares outstanding are listed as 132,344,849 as of the figures in this notice.
The seller acquired 126,193 common shares on 11/20/2025 via a release of restricted stock units from the issuer as compensation. The notice also reports that during the past three months, Kang Sun sold 1,000,000 common shares on 11/17/2025 for gross proceeds of 10,595,300. By signing the notice, the seller represents that they are not aware of any undisclosed material adverse information about AMPX’s current or prospective operations.
A holder of AMPX common stock filed a Form 144 notice to sell 25,024 shares through Morgan Stanley Smith Barney LLC on the NYSE, with an aggregate market value of 252,274. These shares are part of a larger base of 132,344,849 shares outstanding of the issuer’s common stock. The seller recently acquired 52,256 common shares on 11/20/2025 through the release of restricted stock units as compensation, and now plans to begin sales around 11/21/2025. By signing the notice, the seller represents that they are not aware of any undisclosed material adverse information about the issuer’s current or prospective operations.
Amprius Technologies, Inc. (AMPX) filed a Form 4 reporting insider transactions by its Chief Executive Officer and director, Kang Sun, on 11/17/2025. Sun exercised multiple stock options for Amprius common stock at exercise prices of $0.98, $0.05, and $0.62 per share and then reported an open market sale of 1,000,000 shares at an average price of $10.5953 per share.
The filing states these option exercises and related sales were carried out under a Rule 10b5-1 trading plan adopted on August 18, 2025. After the reported transactions, Sun beneficially owned 1,472,306 shares directly, which includes 1,411,769 restricted stock units, and an additional 274,275 shares indirectly through a family trust where he and his spouse serve as co-trustees.
A shareholder of AMPX filed a Form 144 notice to sell 1,000,000 shares of common stock through Morgan Stanley Smith Barney LLC on the NYSE, with an aggregate market value of $11,290,000. The table shows 130,483,838 shares of common stock outstanding. The shares to be sold were acquired on 11/17/2025 by exercising stock options for cash on the same date.
Over the past three months, an individual named Kang Sun sold 65,654 common shares for gross proceeds of $447,510.79. The signer represents that they are not aware of undisclosed material adverse information about AMPX’s current or prospective operations at the time of this planned sale.