Weichai Reporting Persons Reduce PSIX Stake to 49.8% After Rule 144 Sales

Rhea-AI Filing Summary

Amendment No. 6 to a Schedule 13D reports that Weichai America Corp., together with affiliated reporting persons Weichai Power Co., Ltd. and Shandong Heavy Industry Group Co., Ltd., sold an aggregate of 285,935 shares of Power Solutions International, Inc. common stock in open-market transactions under Rule 144 on August 12-13, 2025. The sales were executed through a broker-dealer at weighted average prices of $93.8053 on August 12 and $89.8283 on August 13, with reported price ranges provided for each day. Following these transactions the reporting persons disclose beneficial ownership of 11,463,824 shares, representing 49.8% of the outstanding common stock based on 23,029,846 shares outstanding as of July 31, 2025.

Insights

Financial Analyst

TL;DR: Open-market Rule 144 sales of 285,935 shares reduced combined stake to 49.8%, with modest price realization in mid-$80s to high-$90s.

The transactions are disclosed clearly, including per-day share counts and weighted average prices, which aids transparency for investors tracking insider dispositions. The remaining combined stake of 49.8% means the reporting persons remain the largest holder but dropped below a majority, which could modestly reduce their consolidated voting control. The sales do not indicate acquisition activity or additional financing; they are routine Rule 144 dispositions with materiality limited to ownership percentage change.

Corporate Governance Expert

TL;DR: Beneficial owners sold shares under Rule 144, lowering reported ownership to 49.8%, a disclosure-driven change in governance influence.

The filing documents the mechanics of the sale and updates beneficial ownership precisely, satisfying disclosure obligations. Dropping under 50% is governance-relevant because it formally places the reporting group below a majority threshold, potentially affecting voting dynamics on shareholder actions requiring majority control. No other governance changes or arrangements are disclosed.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 6)

POWER SOLUTIONS INTERNATIONAL, INC.

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

73933G202

(CUSIP Number)

Weichai America Corp.
Attn: Jinguang Liu (aka Jin Liu), 3100 Golf Road
Rolling Meadows, IL, 60008
(855-922-9001)

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

08/13/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 73933G202

1

Name of reporting person

Weichai America Corp.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

ILLINOIS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 11,463,824.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 11,463,824.00

11

Aggregate amount beneficially owned by each reporting person

11,463,824.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

49.8 %

14

Type of Reporting Person (See Instructions)

CO

Comment for Type of Reporting Person:

1. The number of shares beneficially owned represents 11,463,824 shares of Common Stock held by the Reporting Persons. 2. The beneficial ownership percentage is calculated in accordance with Rule 13d-3 under the Securities Exchange Act of 1934, as amended, based upon information from the Issuer's Quarterly Report on Form 10-Q filed on August 8, 2025 that, as of July 31, 2025, there were 23,029,846 shares of Common Stock outstanding.

SCHEDULE 13D

CUSIP No. 73933G202

1

Name of reporting person

Weichai Power Co., Ltd.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CHINA

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 11,463,824.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 11,463,824.00

11

Aggregate amount beneficially owned by each reporting person

11,463,824.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

49.8 %

14

Type of Reporting Person (See Instructions)

CO

Comment for Type of Reporting Person:

1. The number of shares beneficially owned represents 11,463,824 shares of Common Stock held by the Reporting Persons. 2. The beneficial ownership percentage is calculated in accordance with Rule 13d-3 under the Securities Exchange Act of 1934, as amended, based upon information from the Issuer's Quarterly Report on Form 10-Q filed on August 8, 2025 that, as of July 31, 2025, there were 23,029,846 shares of Common Stock outstanding.

SCHEDULE 13D

CUSIP No. 73933G202

1

Name of reporting person

Shandong Heavy Industry Group Co., Ltd.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CHINA

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 11,463,824.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 11,463,824.00

11

Aggregate amount beneficially owned by each reporting person

11,463,824.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

49.8 %

14

Type of Reporting Person (See Instructions)

CO

Comment for Type of Reporting Person:

1. The number of shares beneficially owned represents 11,463,824 shares of Common Stock held by the Reporting Persons. 2. The beneficial ownership percentage is calculated in accordance with Rule 13d-3 under the Securities Exchange Act of 1934, as amended, based upon information from the Issuer's Quarterly Report on Form 10-Q filed on August 8, 2025 that, as of July 31, 2025, there were 23,029,846 shares of Common Stock outstanding.

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.001 per share
(b)	Name of Issuer: POWER SOLUTIONS INTERNATIONAL, INC.
(c)	Address of Issuer's Principal Executive Offices: 201 Mittel Drive, Wood Dale, ILLINOIS , 60191.
Item 1 Comment: This constitutes Amendment No. 6 ("Amendment No. 6") to the Schedule 13D relating to the shares of Common Stock of Power Solutions International, Inc. (the "Issuer") as filed with the SEC on April 7, 2017, as amended by Amendment No. 1, Amendment No. 2, Amendment No. 3, Amendment No. 4 and Amendment No. 5 as filed with the SEC on August 10, 2017, December 5, 2017, August 31, 2018, October 3, 2018 and April 26, 2019, respectively (as so amended, the "Schedule 13D"), by Weichai America Corp. ("Weichai America"), Weichai Power Co., Ltd. ("Weichai Power"), and Shandong Heavy Industry Group Co., Ltd. ("SHIG") (each of Weichai America, Weichai Power, and SHIG a "Reporting Person" and collectively the "Reporting Persons"). Capitalized terms used in this Amendment No. 6 without being defined herein have the respective meanings given to them in the Schedule 13D. This Amendment No. 6 is being filed by the Reporting Persons to report the open market sales by Weichai America of an aggregate of 285,935 shares of the Issuer's Common Stock pursuant to Rule 144 under the Securities Act of 1933, as amended ("Rule 144"), through a broker-dealer from August 12, 2025 to August 13, 2025 (the "Sales"). The Sales resulted in a decrease of over one percent (1%) in the aggregate percentage ownership reported by the Reporting Persons in Amendment No. 5 to the Schedule 13D. Except as specifically amended by this Amendment No. 6, this Schedule 13D is not modified or revised in any way.
Item 4.	Purpose of Transaction
	Item 4 is hereby amended and supplemented by adding the following: On August 8, 2025, Weichai Amercia filed a notice with the SEC on Form 144 relating to the proposed sale of up to 1,150,000 shares of Common Stock in accordance with Rule 144. From August 12, 2025 to August 13, 2025, the Reporting Persons sold an aggregate of 285,935 shares of Common Stock in a series of open-market transactions through a broker-dealer pursuant to Rule 144.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5(a) is hereby amended and restated as set forth below: The Reporting Persons may be deemed to beneficially own the shares of Common Stock of the Issuer as set forth on Exhibit Q hereto.
(b)	Item 5(b) is hereby amended and restated as set forth below: The Reporting Persons may be deemed to beneficially own the shares of Common Stock of the Issuer as set forth on Exhibit Q hereto.
(c)	Item 5(c) is hereby amended and restated as set forth below: In connection with the Sales, Weichai America sold 285,935 shares of Common Stock in a series of open-market transactions, through a broker-dealer, pursuant to Rule 144. Details by date, listing the number of shares of Common Stock disposed of and the weighted average price per share, are provided below. August 12, 2025 - Shares Disposed of: 123,822 - Weighted Average Price Per Share: $93.8053 (multiple transactions at prices ranging from $87.83 to $97.02 inclusive) August 13, 2025 - Shares Disposed of: 162,113 - Weighted Average Price Per Share: $89.8283 (multiple transactions at prices ranging from $86.09 to $96.335 inclusive) The Reporting Persons undertake to provide, upon request by the staff of the SEC, the Issuer, or a security holder of the Issuer, full information regarding the number of shares sold at each separate price for each of the above transactions. Except as set forth above, none of the Reporting Persons has effected any transaction in shares of Common Stock during the past 60 days.
(d)	Not Applicable.
(e)	Not Applicable.
Item 7.	Material to be Filed as Exhibits.
	Exhibit Q - Beneficial Ownership of the Reporting Persons in the Securities of Power Solutions International, Inc. Exhibit R - Powers of Attorney (Weichai Power Co., Ltd.), incorporated by reference to Exhibit 24.1 to the Form 4 filed by Reporting Persons with the Securities and Exchange Commission on August 14, 2025. Exhibit S - Power of Attorney (Shandong Heavy Industry Group Co., Ltd.), incorporated by reference to Exhibit 24.2 to the Form 4 filed by Reporting Persons with the Securities and Exchange Commission on August 14, 2025.

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.

Weichai America Corp.

Signature:	/s/ Jinguang Liu (aka Jin Liu)
Name/Title:	Jinguang Liu (aka Jin Liu), Chief Financial Officer
Date:	08/15/2025

Weichai Power Co., Ltd.

Signature:	/s/ Chenglong Sun
Name/Title:	Chenglong Sun, Authorized Representative
Date:	08/15/2025

Shandong Heavy Industry Group Co., Ltd.

Signature:	/s/ Chenglong Sun
Name/Title:	Chenglong Sun, Authorized Representative
Date:	08/15/2025

FAQ

How many PSIX shares did Weichai America sell on August 12-13, 2025?

Weichai America sold an aggregate of 285,935 shares of PSIX in open-market transactions on August 12-13, 2025.

What prices were realized for the PSIX shares sold by the reporting persons?

Weighted average prices were $93.8053 on August 12, 2025 and $89.8283 on August 13, 2025, with intra-day ranges disclosed in the filing.

What is the reporting persons' ownership percentage in PSIX after the sales?

After the transactions the reporting persons report beneficial ownership of 11,463,824 shares, representing 49.8% of outstanding common stock based on 23,029,846 shares outstanding as of July 31, 2025.

Under what authority were the PSIX shares sold?

The sales were effected in a series of open-market transactions through a broker-dealer pursuant to Rule 144 under the Securities Act.

Were there any other transactions by the reporting persons in the past 60 days?

The filing states that, except for the disclosed sales, none of the reporting persons effected any transaction in PSIX during the past 60 days.