C3is Inc. received a Schedule 13G from CVI Investments, Inc. and Heights Capital Management, Inc. reporting beneficial ownership of 1,221,154 Shares of common stock, representing 9.9% of the class. The position consists of 980,000 Shares plus additional Shares issuable upon exercise of warrants.
The warrants are subject to a 9.99% beneficial ownership cap, preventing exercises that would push combined ownership above that level under Section 13(d) rules. Based on company information, there were 11,982,612 Shares outstanding (excluding Shares underlying the warrants) as of the completion of the referenced offering. Heights Capital, as investment manager to CVI, may be deemed to share voting and dispositive power, though both Reporting Persons disclaim beneficial ownership beyond their pecuniary interest.
Positive
None.
Negative
None.
Key Figures
Beneficial ownership:1,221,154 SharesCommon Shares held:980,000 SharesOwnership percentage:9.9 %+2 more
5 metrics
Beneficial ownership1,221,154 SharesShares of C3is common stock reported as beneficially owned by the Reporting Persons
Common Shares held980,000 SharesPortion of the reported position that is outstanding C3is common stock
Ownership percentage9.9 %Percentage of C3is common stock class represented by the reported 1,221,154 Shares
Beneficial ownership cap9.99 %Maximum beneficial ownership allowed for warrant exercises by the Reporting Persons
Shares outstanding11,982,612 SharesC3is common shares outstanding, excluding warrant shares, at completion of the referenced offering
Key Terms
beneficial owner, Shared Voting Power, Shared Dispositive Power, Limited Power of Attorney, +1 more
5 terms
beneficial ownerregulatory
"may be deemed to be the beneficial owner of all Shares owned"
A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.
Shared Voting Powerregulatory
"6 | Shared Voting Power 1,221,154.00 7 | Sole Dispositive Power"
Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.
Shared Dispositive Powerregulatory
"8 | Shared Dispositive Power 1,221,154.00 9 1,221,154.00"
Limited Power of Attorneyregulatory
"authorized agent of CVI Investments, Inc. pursuant to a Limited Power of Attorney"
Section 13(d) of the Exchange Actregulatory
"aggregated with such Reporting Person for purposes of Section 13(d) of the Exchange Act"
What ownership stake in C3is Inc. (CISS) do CVI Investments and Heights Capital report?
CVI Investments and Heights Capital report beneficial ownership of 1,221,154 C3is common shares, representing 9.9% of the outstanding common stock, including shares underlying warrants subject to an ownership cap.
How many C3is Inc. (CISS) shares are currently outstanding?
Based on company information, there were 11,982,612 C3is common shares outstanding, excluding shares underlying warrants, as of the completion of the offering described in the company’s July 28, 2026 prospectus.
What portion of CVI Investments’ C3is (CISS) position is common stock versus warrants?
The reported 1,221,154-share position in C3is includes 980,000 common shares plus additional shares issuable upon exercise of warrants, which are restricted by a 9.99% beneficial ownership limitation.
What is the beneficial ownership limitation on the C3is (CISS) warrants?
The C3is warrants held by the Reporting Persons are not exercisable to the extent exercise would cause their beneficial ownership to exceed 9.99% of the outstanding common shares under Section 13(d) rules.
What role does Heights Capital play in the C3is Inc. (CISS) share position?
Heights Capital Management, Inc. is the investment manager to CVI Investments, Inc. and may exercise voting and dispositive power over the 1,221,154 shares reported, while disclaiming beneficial ownership beyond its pecuniary interest.
Which entities jointly filed the Schedule 13G for C3is Inc. (CISS)?
The Schedule 13G for C3is was jointly filed by CVI Investments, Inc. and Heights Capital Management, Inc. under a Joint Filing Agreement, with Heights Capital acting under a Limited Power of Attorney for CVI.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
C3is Inc.
(Name of Issuer)
Common Stock, $0.01 par value per share
(Title of Class of Securities)
Y18284300
(CUSIP Number)
07/27/2026
(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):
Y18284300
1
Names of Reporting Persons
CVI Investments, Inc.
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
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,221,154.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,221,154.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,221,154.00
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)
9.9 %
12
Type of Reporting Person (See Instructions)
CO
Comment for Type of Reporting Person: With respect to Row 6 and Row 8 above, Heights Capital Management, Inc. is the investment manager to CVI Investments, Inc. and as such may exercise voting and dispositive power over the shares reported as beneficially owned by CVI Investments, Inc. herein.
SCHEDULE 13G
CUSIP Number(s):
Y18284300
1
Names of Reporting Persons
Heights Capital Management, Inc.
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
1,221,154.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,221,154.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,221,154.00
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)
9.9 %
12
Type of Reporting Person (See Instructions)
CO
Comment for Type of Reporting Person: With respect to Row 6 and Row 8 above, Heights Capital Management, Inc. is the investment manager to CVI Investments, Inc. and as such may exercise voting and dispositive power over the shares reported as beneficially owned by CVI Investments, Inc. herein.
This statement is filed by the entities listed below, who are collectively referred to herein as "Reporting Persons," with respect to the shares of common stock of C3is Inc. (the "Company"), $0.01 par value per share (the "Shares").
(i) CVI Investments, Inc.
(ii) Heights Capital Management, Inc.
(b)
Address or principal business office or, if none, residence:
The address of the principal business office of CVI Investments, Inc. is:
P.O. Box 309GT
Ugland House
South Church Street
George Town
Grand Cayman
KY1-1104
Cayman Islands
The address of the principal business office of Heights Capital Management, Inc. is:
101 California Street, Suite 3250
San Francisco, California 94111
(c)
Citizenship:
Citizenship is set forth in Row 4 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person.
(d)
Title of class of securities:
Common Stock, $0.01 par value per share
(e)
CUSIP Number(s):
Y18284300
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:
The information required by this Item 4(a) is set forth in Row 9 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person.
The number of Shares reported as beneficially owned consists of (i) 980,000 Shares, and (ii) Shares issuable upon the exercise of warrants to purchase Shares (the "Warrants"). The Warrants are not exercisable to the extent that the total number of Shares then beneficially owned by a Reporting Person and its affiliates and any other persons whose beneficial ownership of Shares would be aggregated with such Reporting Person for purposes of Section 13(d) of the Exchange Act, would exceed 9.99%.
Based on information provided by the Company, there were 11,982,612 Shares outstanding (excluding Shares underlying the Warrants) as of the completion of the offering of Shares described in its Prospectus (Registration No. 333-297627), filed on July 28, 2026.
(b)
Percent of class:
9.9 %
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
The information required by this Item 4(c)(i) is set forth in Row 5 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person.
(ii) Shared power to vote or to direct the vote:
The information required by this Item 4(c)(ii) is set forth in Row 6 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person.
Heights Capital Management, Inc., which serves as the investment manager to CVI Investments, Inc., may be deemed to be the beneficial owner of all Shares owned by CVI Investments, Inc. Each of the Reporting Persons hereby disclaims any beneficial ownership of any such Shares, except for their pecuniary interest therein.
(iii) Sole power to dispose or to direct the disposition of:
The information required by this Item 4(c)(iii) is set forth in Row 7 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person.
(iv) Shared power to dispose or to direct the disposition of:
The information required by this Item 4(c)(iv) is set forth in Row 8 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person.
Heights Capital Management, Inc., which serves as the investment manager to CVI Investments, Inc., may be deemed to be the beneficial owner of all Shares owned by CVI Investments, Inc. Each of the Reporting Persons hereby disclaims any beneficial ownership of any such Shares, except for their pecuniary interest therein.
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:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above 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.
CVI Investments, Inc.
Signature:
/s/ Sarah Travis
Name/Title:
Sarah Travis, Assistant General Counsel and Assistant Secretary of Heights Capital Management, Inc.
Date:
08/03/2026
Heights Capital Management, Inc.
Signature:
/s/ Sarah Travis
Name/Title:
Sarah Travis, Assistant General Counsel and Assistant Secretary
Date:
08/03/2026
Comments accompanying signature: Heights Capital Management, Inc. serves as authorized agent of CVI Investments, Inc. pursuant to a Limited Power of Attorney, a copy of which is attached as Exhibit 24 hereto.
Exhibit Information
EXHIBIT INDEX
EXHIBIT DESCRIPTION
________ ________
24 Limited Power of Attorney
99 Joint Filing Agreement
