SEACOR Marine holder reports 5.1% stake

SEACOR Marine Holdings Inc. received a Schedule 13G from an investor group led by Carl K. Oppenheimer reporting beneficial ownership of common stock.

Rhea-AI Filing Summary

SEACOR Marine Holdings Inc. received a Schedule 13G from an investor group led by Carl K. Oppenheimer reporting beneficial ownership of common stock. The filing states that Carl K. Oppenheimer is deemed to beneficially own 1,383,792 shares, representing 5.1% of the common stock. Related entities report additional positions, including P. Oppenheimer Investment Partnership, LP with 530,010 shares (2.0%), Oppenheimer-Close Investment Partnership, LP with 147,961 shares (0.6%), Oppenheimer + Close, LLC with 705,821 shares (2.6%), and Oppvest, LLC with 677,971 shares (2.5%). All reported holdings have sole voting and dispositive power and no shared voting or dispositive power.

Key Figures

Beneficial ownership: 1,383,792 shares P. Oppenheimer Investment Partnership holding: 530,010 shares Oppenheimer-Close Investment Partnership holding: 147,961 shares +3 more

6 metrics

Beneficial ownership 1,383,792 shares Shares of SEACOR Marine common stock beneficially owned by Carl K. Oppenheimer, 5.1% of class

P. Oppenheimer Investment Partnership holding 530,010 shares Amount beneficially owned, representing 2.0% of SEACOR Marine common stock

Oppenheimer-Close Investment Partnership holding 147,961 shares Amount beneficially owned, representing 0.6% of SEACOR Marine common stock

Oppenheimer + Close, LLC holding 705,821 shares Amount beneficially owned, representing 2.6% of SEACOR Marine common stock

Oppvest, LLC holding 677,971 shares Amount beneficially owned, representing 2.5% of SEACOR Marine common stock

Sole voting power, Carl K. Oppenheimer 780,737 shares Shares over which Carl K. Oppenheimer has sole voting and dispositive power

Key Terms

beneficially owned, sole voting power, sole dispositive power, Schedule 13G

4 terms

beneficially owned financial

"Item 4. | Ownership (a) | Amount beneficially owned: 530,010 147,961 705,821 677,971 1,383,792"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

sole voting power financial

"(i) Sole power to vote or to direct the vote: 530,010 147,961 102,766 677,971 780,737"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

sole dispositive power financial

"(iii) Sole power to dispose or to direct the disposition of: 530,010 147,961 102,766 677,971 780,737"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

Schedule 13G regulatory

"SEACOR Marine Holdings Inc. received a Schedule 13G from an investor group"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What ownership stake in SEACOR Marine (SMHI) does Carl K. Oppenheimer report?

Carl K. Oppenheimer reports beneficial ownership of 1,383,792 shares of SEACOR Marine common stock, representing 5.1% of the outstanding class, according to the Schedule 13G filing by him and affiliated entities.

Which entities are included in the SEACOR Marine (SMHI) Schedule 13G filing?

The filing lists P. Oppenheimer Investment Partnership, LP, Oppenheimer-Close Investment Partnership, LP, Oppenheimer + Close, LLC, Oppvest, LLC, and Carl K. Oppenheimer as reporting persons for SEACOR Marine common stock.

How many SEACOR Marine (SMHI) shares does P. Oppenheimer Investment Partnership, LP hold?

P. Oppenheimer Investment Partnership, LP reports 530,010 shares of SEACOR Marine common stock, equal to 2.0% of the class, all with sole voting and sole dispositive power and no shared power.

What percentage of SEACOR Marine (SMHI) does Oppvest, LLC beneficially own?

Oppvest, LLC reports 677,971 shares of SEACOR Marine common stock, representing 2.5% of the outstanding class, with sole voting and sole dispositive power and no shared authority over the shares.

Does the SEACOR Marine (SMHI) Schedule 13G report any shared voting power?

No. The Schedule 13G states that each reporting person has 0 shares with shared voting power and 0 shares with shared dispositive power; all reported shares are held with sole voting and dispositive power.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 08/11/2026 - 02:25 PM EDT Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

SEACOR Marine Holdings Inc.

(Name of Issuer)

Common Stock, par value $.01 per share

(Title of Class of Securities)

78413P101

(CUSIP Number)

06/30/2026

(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)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 78413P101

1

Names of Reporting Persons

P. Oppenheimer Investment Parternship, LP

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 530,010.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 530,010.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

530,010.00

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)

1.95 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 78413P101

1

Names of Reporting Persons

Oppenheimer-Close Investment Partnership, LP

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 147,961.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 147,961.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

147,961.00

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)

0.55 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 78413P101

1

Names of Reporting Persons

Oppenheimer + Close, 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 102,766.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 102,766.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

705,821.00

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)

2.6 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP Number(s): 78413P101

1

Names of Reporting Persons

Oppvest, 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 677,971.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 677,971.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

677,971.00

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)

2.5 %

12

Type of Reporting Person (See Instructions)

OO, IA

SCHEDULE 13G

CUSIP Number(s): 78413P101

1

Names of Reporting Persons

Carl K. Oppenheimer

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 780,737.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 780,737.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,383,792.00

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)

IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: SEACOR Marine Holdings Inc.
(b)	Address of issuer's principal executive offices: 12121 Wickchester Lane, Suite 500, Houston, TEXAS 77079
Item 2.
(a)	Name of person filing: P. Oppenheimer Investment Partnership, LP Oppenheimer-Close Investment Partnership, LP Oppenheimer + Close, LLC Oppvest, LLC Carl K. Oppenheimer
(b)	Address or principal business office or, if none, residence: 119 West 57th Street Suite 1515 New York, NY 10019
(c)	Citizenship: Delaware Delaware Delaware Delaware USA
(d)	Title of class of securities: Common Stock, par value $.01 per share
(e)	CUSIP Number(s): 78413P101
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: 530,010 147,961 705,821 677,971 1,383,792
(b)	Percent of class: 2.0% 0.6% 2.6% 2.5% 5.1
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 530,010 147,961 102,766 677,971 780,737
	(ii) Shared power to vote or to direct the vote: 0 0 0 0 0
	(iii) Sole power to dispose or to direct the disposition of: 530,010 147,961 102,766 677,971 780,737
	(iv) Shared power to dispose or to direct the disposition of: 0 0 0 0 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
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:
	Not Applicable

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.

P. Oppenheimer Investment Parternship, LP

Signature:	Carl K. Oppenheimer
Name/Title:	Managing Member
Date:	08/11/2026

Oppenheimer-Close Investment Partnership, LP

Signature:	Carl K. Oppenheimer
Name/Title:	Managing Member
Date:	08/11/2026

Oppenheimer + Close, LLC

Signature:	Carl K. Oppenheimer
Name/Title:	Managing Member
Date:	08/11/2026

Oppvest, LLC

Signature:	Carl K. Oppenheimer
Name/Title:	Managing Member
Date:	08/11/2026

Carl K. Oppenheimer

Signature:	Carl K. Oppenheimer
Name/Title:	Managing Member
Date:	08/11/2026