Amprius Technologies switches auditor to Deloitte

Amprius Technologies, Inc. is changing its independent auditor.

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Form Type

8-K

Rhea-AI Filing Summary

Amprius Technologies, Inc. is changing its independent auditor. The audit committee approved the engagement of Deloitte & Touche LLP to audit the company’s consolidated financial statements for the year ending December 31, 2026, effective April 21, 2026.

On April 17, 2026, the audit committee dismissed BDO USA, P.C., which had audited the company for the years ended December 31, 2025 and 2024. BDO’s prior reports did not contain adverse or disclaimed opinions and were not qualified or modified as to audit scope or accounting principles, and the company states there were no disagreements and no reportable events under Regulation S-K Item 304.

Insights

Auditor switch to Deloitte with no reported disputes is largely procedural.

Amprius Technologies is replacing long-time auditor BDO USA, P.C. with Deloitte & Touche LLP for the 2026 audit. Auditor changes can reflect evolving needs as companies grow, such as broader global capabilities or sector expertise.

The company reports that BDO’s opinions on the 2024 and 2025 financials were clean and that there were no disagreements or reportable events under Item 304 of Regulation S‑K. This language is intended to signal that the change is not driven by disclosed accounting disputes.

The filing also notes that BDO provided a letter to the SEC dated April 21, 2026 regarding these disclosures. Investors may focus on how smoothly the 2026 audit transition proceeds and whether future filings maintain consistent accounting policies and disclosure quality under Deloitte.

8-K Event Classification

2 items: 4.01, 9.01

2 items

Item 4.01 Changes in Registrant's Certifying Accountant Governance

The company changed its independent auditing firm, which may involve disagreements on accounting matters.

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, or exhibit attachments filed with this report.

Key Figures

New audit year: Year ending December 31, 2026 Prior audit years: Years ended December 31, 2025 and 2024 Audit committee decision date: April 17, 2026 +2 more

5 metrics

New audit year Year ending December 31, 2026 Audit engagement for Deloitte & Touche LLP

Prior audit years Years ended December 31, 2025 and 2024 Years audited by BDO USA, P.C.

Audit committee decision date April 17, 2026 Date Deloitte was approved and BDO was dismissed

Deloitte engagement effective date April 21, 2026 Effective date of Deloitte’s appointment

BDO SEC letter date April 21, 2026 Date of BDO letter filed as Exhibit 16.1

Key Terms

Audit Committee, independent registered public accounting firm, Item 304(a)(1)(iv) of Regulation S-K, reportable events, +2 more

6 terms

Audit Committee financial

"On April 17, 2026, the Audit Committee (the "Audit Committee") of the board of directors"

A company's audit committee is a small group of board members who act like independent inspectors for the firm's finances, overseeing how financial reports are prepared, monitoring internal controls, and managing the relationship with external auditors. Investors care because a strong audit committee reduces the risk of accounting errors, fraud, or misleading statements, making financial statements more trustworthy and helping protect shareholder value.

independent registered public accounting firm financial

"approved the engagement of Deloitte & Touche LLP ("Deloitte") as the Company's independent registered public accounting firm"

An independent registered public accounting firm is an outside accounting company officially registered with the government regulator to examine and report on a public company's financial records and controls. Investors treat its reports like an impartial inspector’s certificate — they add credibility to financial statements, help spot errors or misleading claims, and reduce the risk that shareholders are relying on unchecked or biased numbers.

Item 304(a)(1)(iv) of Regulation S-K regulatory

"there were (i) no disagreements within the meaning of Item 304(a)(1)(iv) of Regulation S-K"

reportable events regulatory

"and (ii) no reportable events (within the meaning of Item 304(a)(1)(v) of Regulation S-K)"

Reportable events are significant incidents or changes a company is legally required to disclose to regulators and the public, such as major safety problems, legal actions, financial irregularities, or management changes. They matter to investors because these events can alter a company’s risk profile or future performance, much like a dashboard warning light signals a problem that could affect a car’s safety or reliability. Timely disclosure helps investors make informed decisions and maintain market fairness.

Emerging growth company regulatory

"Emerging growth company x"

An emerging growth company is a recently public or smaller public firm that qualifies for temporary, lighter regulatory and disclosure rules to reduce the cost and effort of being public. For investors, it means the company may provide less historical financial detail and face fewer reporting requirements than larger firms, so it can grow more quickly but also carries higher uncertainty—like buying a promising early-stage product with fewer user reviews.

Exhibit 16.1 regulatory

"A copy of BDO's letter, dated April 21, 2026, is filed as Exhibit 16.1"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What auditor change did Amprius Technologies (AMPX) announce?

Amprius Technologies’ audit committee approved hiring Deloitte & Touche LLP as its independent registered public accounting firm for the year ending December 31, 2026. At the same time, it dismissed BDO USA, P.C., which had previously audited the company’s 2024 and 2025 financial statements.

Were there any disagreements between Amprius Technologies (AMPX) and BDO?

The company states there were no disagreements with BDO under Item 304(a)(1)(iv) of Regulation S‑K. This covers accounting principles, financial statement disclosure, and audit scope or procedures, and notes that no unresolved issues caused BDO to reference disputes in its audit opinions.

How did BDO’s prior audit opinions for Amprius Technologies (AMPX) look?

BDO’s reports on Amprius Technologies’ financial statements as of December 31, 2025 and 2024 did not include adverse opinions or disclaimers of opinion. The reports were also not qualified or modified regarding audit scope or the accounting principles applied in those financial statements.

What are ‘reportable events’ mentioned in the Amprius Technologies (AMPX) filing?

Reportable events, defined in Item 304(a)(1)(v) of Regulation S‑K, include certain issues like internal control problems or auditor concerns. Amprius Technologies states there were no such reportable events with BDO for 2024, 2025, or the interim period through April 17, 2026.

Did BDO respond to Amprius Technologies’ (AMPX) disclosure about the auditor change?

Yes. Amprius requested a letter from BDO addressed to the SEC stating whether it agreed with the company’s statements. BDO’s response letter, dated April 21, 2026, was filed as Exhibit 16.1 to the report detailing the change in independent auditors.

From what date is Deloitte’s appointment as Amprius Technologies’ (AMPX) auditor effective?

Deloitte & Touche LLP’s engagement as Amprius Technologies’ independent registered public accounting firm is effective as of April 21, 2026. Deloitte is expected to audit the company’s consolidated financial statements for the fiscal year ending December 31, 2026 under this appointment.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 04/21/2026 - 04:58 PM EDT

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

_________________________

FORM 8-K

_________________________

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 17, 2026

_________________________

Amprius Technologies, Inc.

(Exact name of Registrant as Specified in Its Charter)

_________________________


Delaware	001-41314	98-1591811
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(IRS Employer Identification No.)


1180 Page Ave Fremont, California			94538
(Address of Principal Executive Offices)			(Zip Code)

Registrant’s Telephone Number, Including Area Code: (800) 425-8803

N/A

(Former Name or Former Address, if Changed Since Last Report)

_________________________

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:


			o			Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

			o			Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

			o			Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

			o			Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading
Symbol(s)

Name of each exchange
on which registered

Common stock, par value $0.0001 per share

AMPX

The New York Stock Exchange

Redeemable warrants, each exercisable for one share of common stock at an exercise price of $11.50

AMPX.W

The New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company x

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Item 4.01 Changes in Registrant’s Certifying Accountant

On April 17, 2026, the Audit Committee (the "Audit Committee") of the board of directors of Amprius Technologies, Inc. (the "Company") approved the engagement of Deloitte & Touche LLP ("Deloitte") as the Company's independent registered public accounting firm to audit the Company’s consolidated financial statements for the year ending December 31, 2026, effective as of April 21, 2026.

On April 17, 2026, the Audit Committee dismissed BDO USA, P.C. ("BDO"), the Company's independent registered public accounting firm for the year ending December 31, 2025 and prior years, and notified BDO that they will not be engaged to audit the Company's consolidated financial statements for the year ending December 31, 2026.

The reports of BDO on the Company's financial statements as of December 31, 2025 and 2024 did not contain an adverse opinion or a disclaimer of opinion, and was not qualified or modified as to audit scope or accounting principles.

During the years ended December 31, 2025 and 2024, and during the subsequent interim period through April 17, 2026, there were (i) no disagreements within the meaning of Item 304(a)(1)(iv) of Regulation S-K between the Company and BDO on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedures, which disagreement, if not resolved to BDO's satisfaction, would have caused BDO to make reference in connection with their opinion to the subject matter of the disagreement and (ii) no reportable events (within the meaning of Item 304(a)(1)(v) of Regulation S-K).

The Company provided BDO with a copy of the disclosures in this Current Report on Form 8-K (the "Current Report") and requested that BDO furnish the Company with a letter addressed to the Securities and Exchange Commission stating whether it agrees with the statements made by the Company set forth above, and if not, stating the respects in which it does not agree. A copy of BDO's letter, dated April 21, 2026, is filed as Exhibit 16.1 to this Current Report on Form 8-K.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.


Exhibit Number						Description

16.1						Letter from BDO USA, P.C. to the Securities and Exchange Commission, dated April 21, 2026

104						Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.


		AMPRIUS TECHNOLOGIES, INC.

Date: April 21, 2026	By:	/s/ Ricardo C. Rodriguez
		Name: Ricardo C. Rodriguez
		Title: Chief Financial Officer

Source: View Original Filing on SEC EDGAR

Filing Exhibits & Attachments

5 documents

Amprius Technologies switches auditor to Deloitte

Rhea-AI Filing Summary