[SCHEDULE 13G] Ultra Clean Holdings, Inc. SEC Filing

Rhea-AI Filing Summary

Frontier Capital Management Co., LLC disclosed beneficial ownership of 2,754,163 shares of Ultra Clean Holdings, Inc. common stock, representing 6.1% of the class. The filer reports no sole voting or dispositive power; instead it reports shared voting power of 1,615,497 shares and shared dispositive power for 2,754,163 shares. The reporting person is classified as an investment adviser (IA).

The filing includes a certification that the securities are held in the ordinary course of business and not for the purpose of changing or influencing control of the issuer. No group, subsidiary, or additional account-level details or transactions are reported in the statement.

Positive

• Reporting person crossed the 5% threshold with 2,754,163 shares (6.1%) beneficially owned
• Filer reports shared voting power for 1,615,497 shares, indicating potential influence without sole control
• Filing classifies the reporting person as an investment adviser (IA) and includes a certification of ordinary-course holdings

Negative

• None.

Insights

Securities Analyst

TL;DR: Frontier reports a material 6.1% beneficial stake with shared voting influence but no sole control.

The disclosure shows Frontier holds 2,754,163 shares, crossing the 5% reporting threshold and therefore becoming a publicly reportable holder. Shared voting power of 1,615,497 shares indicates the firm may participate in governance discussions but does not claim sole control. The certification that shares are held in the ordinary course suggests no stated intent to seek control. This is a material ownership disclosure but does not, by itself, indicate activist intent or imminent governance change.

Corporate Governance Expert

TL;DR: A passive investment-adviser ownership above 5% that discloses shared voting rights but denies intent to influence control.

Classification as an IA and the explicit certification limit the filing's signal to investors: it documents significant exposure to the issuer without asserting control. The absence of reported group affiliations or subsidiary acquisitions simplifies the ownership picture. For governance, shared voting power is meaningful but insufficient to effect unilateral board changes.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Ultra Clean Holdings, Inc.

(Name of Issuer)

Common stock, par value $0.001 per share

(Title of Class of Securities)

90385V107

(CUSIP Number)

06/30/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 90385V107

1

Names of Reporting Persons

FRONTIER CAPITAL MANAGEMENT CO.,LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,615,497.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,754,163.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,754,163.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.1 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Ultra Clean Holdings, Inc.
(b)	Address of issuer's principal executive offices: 26462 Corporate Avenue Hayward, CA 94545
Item 2.
(a)	Name of person filing: FRONTIER CAPITAL MANAGEMENT CO., LLC
(b)	Address or principal business office or, if none, residence: 99 Summer Street Boston, MA 02110
(c)	Citizenship: Delaware
(d)	Title of class of securities: Common stock, par value $0.001 per share
(e)	CUSIP No.: 90385V107
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 2,754,163
(b)	Percent of class: 6.1%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 1,615,497
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 2,754,163
Item 5.	Ownership of 5 Percent or Less of a Class.
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

FRONTIER CAPITAL MANAGEMENT CO.,LLC

Signature:	Robert E. Phay
Name/Title:	Robert E. Phay, Chief Compliance Officer & General Counsel
Date:	08/14/2025

FAQ

How many Ultra Clean Holdings (UCTT) shares does Frontier Capital own?

Frontier Capital reports beneficial ownership of 2,754,163 shares of Ultra Clean common stock.

What percentage of UCTT does Frontier Capital own?

The filing states Frontier beneficially owns 6.1% of the outstanding class of common stock.

Does Frontier Capital have sole voting or dispositive power over the UCTT shares?

No. The filing reports 0 shares with sole voting power and 0 shares with sole dispositive power.

How many shares does Frontier share voting power over for UCTT?

Frontier reports shared voting power for 1,615,497 shares.

Does the filing indicate Frontier intends to change control of Ultra Clean (UCTT)?

The filing includes a certification that the shares are held in the ordinary course of business and were not acquired and are not held for the purpose of changing or influencing control of the issuer.