Harry Vafias - 18 Mar 2026 Form 3 Insider Report for C3is Inc. (CISS)

Role
Director
Signature
/s/ Nina Pyndiah, Attorney-in-Fact
Issuer symbol
CISS
Transactions as of
18 Mar 2026
Net transactions value
$0
Form type
3
Filing time
18 Mar 2026, 16:17:45 UTC
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Vafias Harry Director C3IS INC., 331 KIFISSIAS AVENUE ERITHREA, ATHENS, GREECE /s/ Nina Pyndiah, Attorney-in-Fact 18 Mar 2026 0001328921

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
holding CISS Common Stock 1,162 18 Mar 2026 Direct
holding CISS Common Stock 3,616 18 Mar 2026 By Arethusa Properties LTD F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
holding CISS Stock Option (Right to Buy) 18 Mar 2026 Common Stock 500 $348.00 Direct F2
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Shares held by Arethusa Properties LTD ("Arethusa"). The Reporting Person controls Arethusa and may be deemed to beneficially own the securities held by Arethusa by virtue of such control. The Reporting Person disclaims beneficial ownership of such securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of his pecuniary interest therein, if any. This report shall not be deemed an admission that the Reporting Person is the beneficial owner of such securities for purposes of Section 16 of the Exchange Act or for any other purpose.
F2 50% of the shares subject to such option are vested and exercisable. The remaining 50% of the shares subject to such option vest and become exercisable on September 16, 2026, subject to the Reporting Person's continuous service to the Issuer on such date.

Remarks:

Exhibit 24 - Power of Attorney