Amprius Technologies, Inc. Form 4 Filings

Amprius Technologies, Inc. (AMPX) reported that Chief Technology Officer Stefan Constantin Ionel sold 29,681 shares of common stock on 2026-08-21 at an average price of $10.341 per share. The sale was a non-discretionary sell-to-cover mandated by the company to fund tax withholding on vested restricted stock units. After the transaction, Ionel directly held 771,629 shares of common stock, including 525,176 restricted stock units, each RSU representing a contingent right to receive one share, subject to vesting conditions.

Amprius Technologies, Inc. (AMPX) reported insider activity by Chief Executive Officer and director Thomas M. Stepien involving sales, gifts, and a transfer of common stock. On August 21, 2026 he sold 23,529 shares at an average of $10.341 per share in multiple trades between $10.10 and $10.48, in a non‑discretionary, issuer‑mandated sell‑to‑cover arrangement for tax withholding tied to restricted stock unit vesting. On August 24, 2026 he sold an additional 8,000 shares at $10.03 per share. On August 25, 2026 he made bona fide gifts totaling 15,346 shares, including 346 shares transferred to the Rogers Stepien Family Revocable Trust. The same 346 shares were recorded as an indirect acquisition by that trust, which held 37,260 shares after the transfer. Reported holdings include 568,750 restricted stock units, each convertible into one share upon vesting.

BAYLESS KATHLEEN A reported acquisition or exercise transactions in this Form 4 filing.

Amprius Technologies, Inc. director Kathleen A. Bayless received a grant of 10,423 restricted stock units, each representing one share of common stock. These units vest 100% on the earlier of the one-year anniversary of the grant date or the day before the next annual stockholders’ meeting, subject to her continued service. Following this award, she directly holds 216,120 shares of common stock, including the 10,423 restricted stock units.

SATTERTHWAITE LIVINGSTON reported acquisition or exercise transactions in this Form 4 filing.

Amprius Technologies director Livingston Satterthwaite received an equity award in the form of restricted stock units. The Form 4 reports a grant of 10,423 restricted stock units, each representing one share of common stock at no cash cost per unit. All of these units vest 100% on the earlier of the one-year anniversary of the grant date or the day before the next annual meeting of stockholders, if he continues to serve through that date. Following this grant, he is reported as beneficially owning 346,506 shares in total, including 199,102 restricted stock units that remain subject to their respective vesting conditions.

Amprius Technologies director Donald R. Dixon reported both an insider sale and an equity award in common stock. An entity associated with him, Donald & Elizabeth Dixon 2004 Family Partners, completed an open-market sale of 85,000 shares of Amprius Technologies common stock at an average price of $17.1672 per share, leaving 359,380 shares held indirectly after the transaction. Separately, Dixon received a grant of 10,423 restricted stock units, each representing one share of common stock, bringing his directly held common stock (including these units) to 280,079 shares.

Chu Steven reported acquisition or exercise transactions in this Form 4 filing.

Amprius Technologies, Inc. director Steven Chu received a grant of 10,423 restricted stock units, each representing the right to receive one share of common stock at no purchase price. The units vest 100% on the earlier of the one-year anniversary of grant or the day before the next annual stockholder meeting, subject to his continued service. Following this award, Chu holds 137,762 shares of the company’s common stock directly, including the 10,423 restricted stock units subject to vesting conditions.

Amprius Technologies director Donald R. Dixon reported an indirect open-market sale of 40,000 shares of common stock at $19.13 per share. The transaction was coded as an open-market sale and involved indirectly held shares tied to family trust and partnership structures described in the footnotes.

After these transactions, Dixon reports 269,656 shares held directly and two separate indirect positions of 163,142 shares and 444,380 shares, respectively. The filing indicates these indirect holdings are through The Dixon Revocable Trust and the Donald & Elizabeth Dixon 2004 Family Partners, where he has roles described in the footnotes.

Amprius Technologies Chief Executive Officer Thomas M. Stepien reported a mix of open-market selling and gifts of company stock. On June 4, 2026, he sold 2,000 shares of common stock at $20.97 per share in an open-market transaction.

On the same date, he made bona fide gifts totaling 104,212 shares of common stock, including transfers to the Rogers Stepien Family Revocable Trust. After these transactions, he holds 625,625 shares directly and 36,914 shares indirectly through the trust, and footnotes state his holdings include 615,625 restricted stock units that may convert into shares over time.

Amprius Technologies director Sun Kang reported a small tax-related share sale. On this Form 4, Kang disclosed an open-market sale of 356 shares of common stock on May 27, 2026 at an average price of $17.1935 per share.

According to the footnotes, this transaction was a non-discretionary sell-to-cover mandated by the company to fund tax withholding on vesting restricted stock units. After the sale, Kang held 1,280,498 shares directly, including 1,038,662 restricted stock units, and 56,406 shares indirectly through the Kang & Cecillia Sun Family Revocable Trust.

Amprius Technologies, Inc. Chief Executive Officer Thomas M. Stepien reported an open-market sale of 4,375 shares of common stock at an average price of $17.1935 per share. According to the disclosure, this was a non-discretionary sell-to-cover transaction mandated by the company to fund tax withholding tied to vesting restricted stock units. After the sale, Stepien directly holds 694,923 shares, which the filing notes include 615,625 restricted stock units that may convert into common shares as their vesting conditions are met.

Amprius Technologies, Inc. Chief Technology Officer Stefan Constantin Ionel reported an open-market sale of 3,208 shares of common stock at an average price of $17.1935 per share. The sale was executed under non-discretionary, sell-to-cover arrangements mandated by the company to fund tax withholding on vested restricted stock units.

Following this tax-related sale, Ionel beneficially owns 801,310 shares, including 584,308 restricted stock units that each represent the right to receive one share of common stock, subject to vesting conditions.

Amprius Technologies director Donald R. Dixon reported an open‑market sale of 17,895 shares of common stock indirectly held through an affiliated entity at $17.8962 per share. After this sale, one indirect position shown holds 484,380 shares, alongside 269,656 shares held directly and another 163,142 shares held indirectly.

Footnotes state that certain indirect holdings are in The Dixon Revocable Trust and the Donald & Elizabeth Dixon 2004 Family Partners, where Dixon is a co‑trustee or co‑general partner. The direct position includes 44,444 restricted stock units that may convert into common shares if vesting conditions are met.

Amprius Technologies director Sun Kang reported an open-market sale of 67,796 shares of common stock on May 21, 2026 at an average price of $14.7884 per share. According to the disclosure, this sale was executed under non-discretionary, sell-to-cover arrangements mandated by the company to fund tax withholding obligations tied to the vesting of restricted stock units.

Following the sale, Kang directly held 1,280,854 common shares, which the filing notes include 1,039,443 restricted stock units, each representing a contingent right to one share subject to vesting conditions. Separately, 56,406 shares are held indirectly through the KANG & CECILLIA SUN FAMILY REVOCABLE TRUST, for which Kang and his spouse serve as co-trustees.

Amprius Technologies, Inc. Chief Technology Officer Stefan Constantin Ionel reported an open-market sale of 28,812 shares of common stock on May 21, 2026 at an average price of $14.7884 per share. According to the disclosure, this sale was a non-discretionary, sell-to-cover transaction mandated by the company to fund tax withholding obligations related to vesting restricted stock units. After the sale, Ionel directly held 804,518 shares of common stock, including 591,183 restricted stock units that may convert into shares as vesting conditions are met.

Amprius Technologies CEO Thomas M. Stepien reported an open-market sale of 60,702 shares of common stock at an average price of $14.7884 per share. According to the disclosure, this non-discretionary sale was mandated by the company to cover tax withholding obligations tied to the vesting of restricted stock units.

After the sale, Stepien holds 699,298 shares directly, which the filing states includes 625,000 restricted stock units that may convert into common shares as they vest under their applicable schedules and conditions.

Stepien Thomas M reported acquisition or exercise transactions in this Form 4 filing.

Amprius Technologies, Inc. reported that Chief Executive Officer Thomas M. Stepien received a grant of 200,000 shares of common stock at a price of $0.00 per share as a compensation-related award. Following this grant, he directly holds 760,000 shares of Amprius common stock.

The amended filing clarifies the vesting schedule for the underlying restricted stock units. 2/16 of the shares will vest on May 20, 2026, and 1/16 will vest quarterly on each August 20, November 20, February 20, and May 20, subject to his continued service, until the award is fully vested on November 20, 2029.

Amprius Technologies, Inc. director Sun Kang received an equity compensation grant of 6,250 shares of common stock in the form of restricted stock units at a price of $0.00 per share. This is a grant/award acquisition rather than an open-market purchase.

Each restricted stock unit represents the right to receive one share of common stock, subject to vesting. One-eighth of the award will vest on May 20, 2026, with additional vesting each quarter on August 20, November 20, February 20 and May 20 until the grant is fully vested on February 20, 2028, assuming continued service. After this grant, Kang directly holds 1,348,650 shares, including 1,165,635 restricted stock units.

Amprius Technologies director Sun Kang exercised stock options and sold shares in a pre-planned trade. On April 1, 2026, he exercised options for a total of 1,500,000 shares of common stock at strike prices of $1.78 and $3.68 per share, then sold 1,500,000 shares in open-market transactions at average prices of $15.7328 and $16.7829, with actual sale prices ranging from $15.37 to $17.31.

Following these transactions, he holds 1,342,400 shares directly and 56,406 shares indirectly through the KANG & CECILLIA SUN FAMILY REVOCABLE TRUST. His holdings also include 1,159,385 restricted stock units, each representing a contingent right to one share. All reported trades were executed under a Rule 10b5-1 trading plan adopted on August 18, 2025, indicating they were pre-scheduled rather than discretionary.

Amprius Technologies director Sun Kang, through the KANG & CECILLIA SUN FAMILY REVOCABLE TRUST, reported open-market sales of a total of 217,869 shares of common stock on March 23, 2026. The shares were sold in two tranches at average prices of $18.6863 and $19.0589, with individual trade prices ranging from $17.89 to $19.36. These transactions were executed under a pre-arranged Rule 10b5-1 trading plan adopted on August 18, 2025. Following the sales, the trust held 56,406 shares indirectly, while Kang also held 1,342,400 shares directly, including 1,159,385 restricted stock units subject to vesting conditions.

RODRIGUEZ RICARDO C. reported acquisition or exercise transactions in this Form 4 filing.

Amprius Technologies, Inc. reported that its Chief Financial Officer, Ricardo C. Rodriguez, received a grant of 150,000 shares of common stock on March 4, 2026 at a price of $0.00 per share. Following this equity award, he directly owns 350,000 shares.

This amended filing corrects the vesting schedule for the previously reported restricted stock units. According to the updated terms, 3/16 of the shares will vest on November 20, 2026, with additional portions vesting quarterly on February 20, May 20, August 20 and November 20 until the award is fully vested on February 20, 2030, subject to his continued service.

Amprius Technologies director Wen Hsuan Hsieh reported an exercise-and-sell transaction in company stock. Hsieh exercised stock options for 270,251 shares of common stock at $2.61 per share, converting a derivative award into directly held shares.

On the same date, Hsieh then sold 282,500 shares of common stock at an average price of $18.546 per share and a further 130,646 shares at an average price of $18.2232 per share in open-market transactions. After these trades, Hsieh reported ownership of 44,444 shares, all in the form of restricted stock units that represent the right to receive common shares if vesting conditions are met.

Amprius Technologies director Steven Chu reported a combination of option exercises and share sales. On March 10 and 12, 2026, he exercised stock options covering 259,697 shares of common stock at exercise prices of $0.62 and $2.61 per share.

Over the same two days, he sold 322,197 shares of common stock in open-market transactions at average prices reported between $17.90 and $18.78 per share. Following these transactions, Chu directly holds 127,339 shares of Amprius common stock, including 44,444 restricted stock units that will settle in shares if vesting conditions are met.

Amprius Technologies, Inc. reported that Chief Financial Officer Ricardo C. Rodriguez acquired 150,000 restricted stock units, each representing one share of common stock, at a price of $0.00 per unit. These units vest 1/16 starting on May 20, 2026 and quarterly thereafter until fully vested on February 20, 2030, subject to continued service. Following this award, he holds 350,000 restricted stock units in total.

Amprius Technologies, Inc. reported that Chief Executive Officer Thomas M. Stepien acquired 150,000 shares of common stock in the form of restricted stock units on March 4, 2026, at a price of $0.00 per share.

Each restricted stock unit represents the right to receive one share of common stock. According to the vesting schedule, 1/16 of the shares subject to the award will vest on May 20, 2026 and then quarterly on each August 20, November 20, February 20 and May 20, subject to his continued service, until the award is fully vested on February 20, 2030.

Following this grant, Stepien directly holds a total of 760,000 shares of common stock, which includes 750,000 restricted stock units that each represent a contingent right to receive one share, subject to their applicable vesting schedules and conditions.

Stefan Constantin Ionel reported acquisition or exercise transactions in this Form 4 filing.

Amprius Technologies, Inc. Chief Technology Officer Stefan Constantin Ionel reported an award of 110,000 shares of common stock in the form of restricted stock units at a price of $0.0000 per share. These RSUs vest 1/16 on May 20, 2026 and then quarterly on August 20, November 20, February 20 and May 20 until fully vested on February 20, 2030. Following this award, he directly holds 833,330 shares/units in total, including 643,440 restricted stock units subject to their respective vesting conditions.

Amprius Technologies director Sun Kang sold 61,251 shares of common stock on February 23, 2026 at an average price of $10.1555. According to the filing, this was a non-discretionary, sell-to-cover transaction mandated by the company to fund tax withholding on vesting restricted stock units.

After this sale, Kang directly holds 1,342,400 shares of Amprius common stock, which includes 1,159,385 restricted stock units. He also has indirect ownership of 274,275 shares through the KANG & CECILLIA SUN FAMILY REVOCABLE TRUST, where he and his spouse serve as co-trustees.

Amprius Technologies Chief Technology Officer Stefan Constantin Ionel reported an open-market sale of 25,366 shares of common stock at an average price of $10.1555 per share. The sale was made under a non-discretionary, issuer-mandated sell-to-cover arrangement for tax withholding on vesting restricted stock units. After the transaction, he holds 723,330 shares, including 533,440 restricted stock units that may convert into common stock as they vest.

Amprius Technologies, Inc. Chief Technology Officer Stefan Constantin Ionel reported option exercises and a related share sale. On January 28, 2026, he exercised stock options for 90 shares at $0.62 and 39,600 shares at $0.05, receiving the same number of common shares.

That same day, he sold 39,690 common shares at an average price of $12.0018, with individual trades ranging from $12.00 to $12.02. After these transactions, he directly beneficially owned 748,696 common shares, including 585,697 restricted stock units. All exercises and sales were made under a Rule 10b5-1 trading plan adopted on September 11, 2025.

Amprius Technologies Chief Technology Officer Stefan Constantin Ionel reported a series of stock option exercises and share sales in January 2026. Between January 21 and 23, 2026, he exercised multiple stock options with exercise prices ranging from $0.05 to $0.62 per share, converting them into common stock.

On those same dates he sold several blocks of common stock, including 73,280 shares at an average price of $12.0007, 492,827 shares at an average price of $12.0365, and 1,600 shares at $12.00, all under a Rule 10b5-1 trading plan adopted on September 11, 2025. Following these transactions, he directly owned 748,696 shares of common stock, which includes 585,697 restricted stock units that may settle into shares if their vesting conditions are met.

Amprius Technologies director Kang Sun reported option exercises and share sales under a pre-arranged trading plan. On January 16, 2026, he exercised stock options for 850,338 shares at $2.5 per share and 100,210 shares at $1.78 per share, then sold 950,548 shares of common stock at an average price of $11.0659 per share. On January 20, 2026, he exercised options for 43,185 shares at $1.78 per share and sold the same number of shares at an average price of $11.0287 per share.

Following these transactions, Sun directly beneficially owned 1,403,651 shares of Amprius common stock, including 1,285,576 restricted stock units, and indirectly held 274,275 shares through the Kang & Cecillia Sun Family Revocable Trust, where he and his spouse are co-trustees. The filing states that the exercises and sales were effected pursuant to a Rule 10b5-1 trading plan adopted on August 18, 2025.

Amprius Technologies director Sun Kang reported multiple option exercises and a share sale. On January 12, 2026, he exercised three stock option grants for 180,802 shares at $0.62, 208,264 shares at $2.44, and 117,201 shares at $2.50 per share, receiving the same number of common shares in each case. He then sold 506,267 shares of common stock at an average price of $10.0964 under a Rule 10b5-1 trading plan adopted on August 18, 2025.

After these transactions, Sun directly beneficially owned 1,403,651 shares of common stock, which includes 1,285,576 restricted stock units, and held 850,338 stock options directly. In addition, 274,275 shares are held indirectly by the KANG & CECILLIA SUN FAMILY REVOCABLE TRUST, for which he and his spouse serve as co-trustees.

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’ 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.

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.

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.

Ricardo C. Rodriguez, Chief Financial Officer of Amprius Technologies, Inc. (AMPX), was granted 200,000 restricted stock units on 10/06/2025. Each restricted stock unit converts to one share of common stock. The award vests 25% on 11/20/2026 with the remainder vesting quarterly on 02/20, 05/20, 08/20 and 11/20 through 11/20/2029, subject to continued service. Following the grant, Mr. Rodriguez beneficially owns 200,000 shares directly. The filing was signed on 10/08/2025.