Solid Power (SLDP) CTO awarded 183,518 RSUs; 14,284 shares withheld

Rhea-AI Filing Summary

Solid Power, Inc. reported that Chief Technology Officer Joshua Buettner-Garrett received a grant of 183,518 shares of common stock on April 1, 2026 at no cost, representing restricted stock units where each unit equals one share. These units vest in 16 equal quarterly installments beginning June 30, 2026, subject to his continued service. On March 31, 2026, 14,284 shares were withheld at $2.82 per share to cover his tax obligation upon vesting of restricted stock units. Following these transactions, he holds 1,279,925 shares of common stock directly.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Buettner-Garrett Joshua

Role Chief Technology Officer

Type	Security	Shares	Price	Value
Grant/Award	Common Stock	183,518	$0.00	--
Tax Withholding	Common Stock	14,284	$2.82	$40K

Holdings After Transaction: Common Stock — 1,463,443 shares (Direct)

Footnotes (1)

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. Each restricted stock unit represents a contingent right to receive one share of the underlying common stock of the Issuer. The restricted stock units will vest in 16 equal quarterly installments commencing on June 30, 2026, and thereafter at the end of each fiscal quarter of the Issuer, subject to the reporting person continuing to be a service provider (as defined in the Solid Power, Inc. 2021 Equity Incentive Plan) through the applicable vesting date.

Key Figures

Stock grant: 183,518 shares Grant price: $0.00 per share Tax withholding shares: 14,284 shares +4 more

7 metrics

Stock grant 183,518 shares Common stock granted on April 1, 2026 as RSUs

Grant price $0.00 per share Reported price per share for the 183,518-share grant

Tax withholding shares 14,284 shares Shares withheld on March 31, 2026 for tax obligation

Tax withholding price $2.82 per share Value used for shares withheld to satisfy taxes

Holdings after grant 1,463,443 shares Total common shares following the April 1, 2026 grant

Final holdings 1,279,925 shares Directly held common shares after both transactions

RSU vesting installments 16 quarterly tranches RSUs vest in 16 equal quarterly installments from June 30, 2026

Key Terms

restricted stock units, tax obligation, service provider, 2021 Equity Incentive Plan

4 terms

restricted stock units financial

"Each restricted stock unit represents a contingent right to receive one share"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

tax obligation financial

"withheld to satisfy the reporting person's tax obligation upon the vesting"

service provider financial

"subject to the reporting person continuing to be a service provider"

2021 Equity Incentive Plan financial

"as defined in the Solid Power, Inc. 2021 Equity Incentive Plan"

Form 4 Insider Transactions: What Each Field Means →

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

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 COLORADO 80027

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/31/2026

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

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

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

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	03/31/2026		F		14,284(1)	D	$2.82	1,279,925	D
Common Stock	04/01/2026		A		183,518(2)	A	$0	1,463,443	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.

2. Each restricted stock unit represents a contingent right to receive one share of the underlying common stock of the Issuer. The restricted stock units will vest in 16 equal quarterly installments commencing on June 30, 2026, and thereafter at the end of each fiscal quarter of the Issuer, subject to the reporting person continuing to be a service provider (as defined in the Solid Power, Inc. 2021 Equity Incentive Plan) through the applicable vesting date.

	/s/ Kristen Gould, attorney-in-fact on behalf of Joshua Buettner-Garrett	04/02/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

What did Solid Power (SLDP) disclose in this Form 4 for its CTO?

Solid Power reported that Chief Technology Officer Joshua Buettner-Garrett received a grant of 183,518 restricted stock units and had 14,284 shares withheld to cover taxes on vesting, leaving him with 1,279,925 directly held common shares after these transactions.

How many Solid Power (SLDP) shares were granted to the CTO in this filing?

The CTO received a grant of 183,518 shares of Solid Power common stock, structured as restricted stock units. Each unit represents the right to receive one share, vesting over time subject to his continued service under the 2021 Equity Incentive Plan.

What is the vesting schedule for the CTO’s Solid Power (SLDP) restricted stock units?

The restricted stock units vest in 16 equal quarterly installments, starting on June 30, 2026. Vesting then continues at the end of each fiscal quarter, conditioned on Joshua Buettner-Garrett remaining a service provider to Solid Power through each applicable vesting date.

Why were 14,284 Solid Power (SLDP) shares withheld from the CTO?

14,284 shares of Solid Power common stock were withheld to satisfy Joshua Buettner-Garrett’s tax obligation when his restricted stock units vested. These shares were valued at $2.82 per share and represent a tax-withholding disposition rather than an open-market sale.

How many Solid Power (SLDP) shares does the CTO own after these transactions?

After the reported grant and tax-withholding disposition, Joshua Buettner-Garrett directly owns 1,279,925 shares of Solid Power common stock. This figure reflects his updated direct holdings following both the 183,518-share grant and the 14,284 shares withheld for taxes.