[Form 4] Solid Power, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Solid Power, Inc. (SLDP) reporting person Joshua Buettner-Garrett, the company's Chief Technology Officer, disclosed a non-derivative disposition on 09/30/2025 where 14,284 shares of common stock were removed from his holdings at a price of $3.52 per share. The filing explains these shares were withheld to satisfy tax obligations upon RSU vesting. After the withholding, Mr. Buettner-Garrett beneficially owns 1,308,493 shares directly. The Form 4 was signed on behalf of the reporting person by an attorney-in-fact on 10/01/2025. The transaction is presented as routine compensation-related withholding rather than an active market sale.

Positive

• Disclosure is compliant: Form 4 filed and signed, showing adherence to insider reporting rules
• Substantial retained ownership: Reporting person continues to hold 1,308,493 shares, maintaining alignment with shareholders

Negative

• Shares disposed (withheld): 14,284 shares withheld to satisfy tax obligations upon RSU vesting

Insights

Financial Analyst

TL;DR: Small, routine RSU tax withholding; ownership remains substantial at 1.308M shares.

The reported disposition of 14,284 shares at $3.52 reflects tax withholding tied to vested restricted stock units, not a discretionary cash-sale by the officer. With 1,308,493 shares remaining, the reporting person retains a material equity stake that continues to align his interests with shareholders. The transaction should have limited market impact given its size relative to total holdings and its administrative nature.

Corporate Governance Expert

TL;DR: Compliance filing demonstrates routine insider reporting and standard tax-withholding practice.

The Form 4 properly discloses the removal of shares to cover tax liabilities from RSU vesting and lists the reporting persons role as Chief Technology Officer. Signature by an attorney-in-fact indicates authorized filing. This is a routine governance event showing compliance with Section 16 reporting obligations; it does not signal a change in control or a shift in executive incentive alignment.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Buettner-Garrett Joshua

(Last) (First) (Middle)

C/O SOLID POWER, INC.

486 S PIERCE AVE., SUITE E

(Street)

LOUISVILLE CO 80027

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Solid Power, Inc. [ SLDP ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Technology Officer

3. Date of Earliest Transaction (Month/Day/Year)
09/30/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/30/2025		F		14,284(1)	D	$3.52	1,308,493	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Represents shares of the issuer's common stock withheld to satisfy the reporting person's tax obligation upon the vesting of restricted stock units.

	/s/ Kristen Gould, attorney-in-fact on behalf of Joshua Buettner-Garrett	10/01/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What transaction did Joshua Buettner-Garrett report on Form 4 for SLDP?

He reported a disposition of 14,284 shares on 09/30/2025, recorded at a price of $3.52 per share.

Why were the 14,284 shares disposed according to the filing?

The filing states the shares were withheld to satisfy tax obligations upon the vesting of restricted stock units.

How many SLDP shares does the reporting person own after the transaction?

After the reported transaction he beneficially owns 1,308,493 shares (direct ownership).

What is the reporting person's role at Solid Power?

The reporting person is listed as the company's Chief Technology Officer.

When was the Form 4 signed and by whom?

The form was signed on behalf of Joshua Buettner-Garrett by an attorney-in-fact, /s/ Kristen Gould, on 10/01/2025.