Oppenheimer group reports up to 5.24% stake in SEACOR

Rhea-AI Filing Summary

SEACOR Marine Holdings Inc. ownership disclosures show affiliated Oppenheimer entities and Carl K. Oppenheimer hold a combined position of 1,412,618 shares (5.24%) reported for one filing party and several affiliated entities with individual holdings listed below.

The filing lists five reporting names with amounts beneficially owned of 530,010, 147,961, 734,647, 677,971, and 1,412,618 shares and corresponding percentages of 2.0%, 0.6%, 2.7%, 2.5%, and 5.2% of the class. Voting and dispositive power are shown as sole powers where indicated.

Insights

Corporate Governance Analyst

Consolidated ownership by related Oppenheimer entities is visible and remains below typical control thresholds.

The filing enumerates five related filers and an individual, listing exact share counts and percent of class figures. Each entry reports sole voting and sole dispositive power for the amounts stated, which clarifies control lines within the group.

Impact on governance is limited by the disclosed 5.24% maximum position size; this is below common takeover or control thresholds, so board influence is incremental. Subsequent filings would show changes in scale or coordination.

Investor Relations Advisor

Disclosure provides clear ownership counts useful for monitoring institutional concentration.

The schedule lists issuer name, CUSIP (78413P101), and five reporting parties with specific share and percent data, aiding transparency about large holders. The address for the filers is shown as 119 West 57th Street, New York.

Investors tracking ownership should note the individual percentages (2.0%, 0.6%, 2.7%, 2.5%, 5.2%) and that voting/dispositive powers are reported as sole for the stated amounts.

Key Figures

Carl K. Oppenheimer holdings: 1,412,618 shares P. Oppenheimer Investment Partnership holdings: 530,010 shares Oppenheimer + Close, LLC holdings: 734,647 shares +2 more

5 metrics

Carl K. Oppenheimer holdings 1,412,618 shares reported beneficially owned

P. Oppenheimer Investment Partnership holdings 530,010 shares reported beneficially owned (2.0% of class)

Oppenheimer + Close, LLC holdings 734,647 shares reported beneficially owned (2.7% of class)

Oppvest, LLC holdings 677,971 shares reported beneficially owned (2.5% of class)

CUSIP 78413P101 SEACOR Marine common stock identifier

Key Terms

beneficially owned, sole dispositive power, CUSIP

3 terms

beneficially owned regulatory

"Amount beneficially owned: 530,010 147,961 734,647 677,971 1,412,618"

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 dispositive power regulatory

"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.

CUSIP market

"CUSIP Number(s): 78413P101"

A CUSIP is a nine-character alphanumeric code that uniquely identifies a U.S. or Canadian financial security—such as a stock, bond, or fund share—like a Social Security number for an investment. It matters to investors because brokers, exchanges and record-keepers use the CUSIP to match trades, track ownership, settle transactions and pull accurate records, reducing errors and ensuring money and securities go to the right place.

FAQ

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

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

Carl K. Oppenheimer is shown with 1,412,618 shares (5.24%). The filing states his sole voting and sole dispositive power over 780,737 of those shares.

Which Oppenheimer entity holds 530,010 shares in SEACOR Marine?

P. Oppenheimer Investment Partnership holds 530,010 shares (2.0%). The schedule lists sole voting and sole dispositive power for that exact share count.

What is the CUSIP for SEACOR Marine common stock in this filing?

The filing identifies the CUSIP as 78413P101. This ties the reported share counts and percentages to SEACOR Marine Holdings Inc. common stock.

Are the reported shares shown as sole or shared voting power?

The entries report sole voting and sole dispositive power for the listed share amounts. Shared voting and shared dispositive power are reported as 0 for each filer.

What address is provided for the filing parties in the Schedule 13G?

The filers list their principal business address as 119 West 57th Street, Suite 1515, New York, NY 10019 in the filing signature block.

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

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Accepted by SEC EDGAR 04/21/2026 - 03:34 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)

03/31/2026

(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)

1.97 %

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

734,647.00

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)

2.73 %

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)

2.52 %

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

1,412,618.00

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)

5.24 %

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: 530,010 147,961 734,647 677,971 1,412,618
(b)	Percent of class: 2.0% 0.6% 2.7% 2.5% 5.2%.
(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:	04/21/2026

Oppenheimer-Close Investment Partnership, LP

Signature:	Carl K. Oppenheimer
Name/Title:	Managing Member
Date:	04/21/2026

Oppenheimer + Close, LLC

Signature:	Carl K. Oppenheimer
Name/Title:	Managing Member
Date:	04/21/2026

Oppvest, LLC

Signature:	Carl K. Oppenheimer
Name/Title:	Managing Member
Date:	04/21/2026

Carl K. Oppenheimer

Signature:	Carl K. Oppenheimer
Name/Title:	Managing Member
Date:	04/21/2026