[SCHEDULE 13G/A] COMFORT SYSTEMS USA INC SEC Filing

Rhea-AI Filing Summary

Capital World Investors filed Amendment No. 1 to a Schedule 13G reporting beneficial ownership of 1,799,310 shares of Comfort Systems USA (FIX) common stock, representing 5.1% of the class as of 09/30/2025.

The filer reports sole voting power over 1,799,310 shares and sole dispositive power over 1,799,310 shares, with no shared power. The percentage is based on 35,281,452 shares believed to be outstanding. The filing is made on a passive basis, certifying the securities were acquired and are held in the ordinary course and not to change or influence control.

Insights

Securities law analyst

Passive 5.1% stake disclosed; administrative update.

Capital World Investors reports a 5.1% beneficial stake in Comfort Systems USA, totaling 1,799,310 shares, as of 09/30/2025. The filer indicates sole voting and sole dispositive power over the same amount and no shared power.

This is a Schedule 13G/A, which signals a passive intent. The certification states the holdings were acquired and are held in the ordinary course and not to influence control. The percentage relies on 35,281,452 shares believed outstanding.

Investor impact tends to be limited for passive 13G updates; actual trading or ownership changes depend on future disclosures by the holder or issuer.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Comfort Systems USA, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

199908104

(CUSIP Number)

09/30/2025

(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. 199908104

1

Names of Reporting Persons

Capital World Investors

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 1,799,310.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 1,799,310.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,799,310.00

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)

5.1 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Comfort Systems USA, Inc.
(b)	Address of issuer's principal executive offices: 9753 KATY FREEWAY, SUITE 700, HOUSTON, TX 77024
Item 2.
(a)	Name of person filing: Capital World Investors
(b)	Address or principal business office or, if none, residence: 333 SOUTH HOPE STREET, 55TH FLOOR, LOS ANGELES, CALIFORNIA 90071
(c)	Citizenship: N/A
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 199908104
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: 1,799,310 ** **Capital World Investors ("CWI") is a division of Capital Research and Management Company ("CRMC"), as well as its investment management subsidiaries and affiliates Capital Bank and Trust Company, Capital International, Inc., Capital International Limited, Capital International Sarl, Capital International K.K., Capital Group Private Client Services, Inc., and Capital Group Investment Management Private Limited (together with CRMC, the "investment management entities"). CWI's divisions of each of the investment management entities collectively provide investment management services under the name "Capital World Investors." CWI is deemed to be the beneficial owner of 1,799,310 shares or 5.1% of the 35,281,452 shares believed to be outstanding.
(b)	Percent of class: 5.1 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 1,799,310
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 1,799,310
	(iv) Shared power to dispose or to direct the disposition of: 0
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.

Capital World Investors

Signature:	Timothy J. Moon
Name/Title:	Vice President and Senior Counsel, Capital Research and Management Company
Date:	11/13/2025

FAQ

What stake did Capital World Investors report in FIX?

They reported beneficial ownership of 1,799,310 shares, or 5.1% of Comfort Systems USA’s common stock.

What is the date of the event for this FIX Schedule 13G/A?

The date of the event requiring the filing is 09/30/2025.

Does Capital World Investors have sole or shared voting power over FIX shares?

They report sole voting power over 1,799,310 shares and no shared voting power.

Is this a passive filing for FIX by Capital World Investors?

Yes. The certification states the securities were acquired and are held in the ordinary course and not to change or influence control.

What share count was used to calculate the 5.1% FIX ownership?

The percentage is based on 35,281,452 shares believed to be outstanding.

Who signed the Schedule 13G/A for Capital World Investors?

It was signed by Timothy J. Moon, Vice President and Senior Counsel, Capital Research and Management Company.