NSTS Bancorp director shares convert at $14.31

The merger set a $14.31 cash entitlement for common shares; the canceled option’s cash formula used its $9.36 exercise price.

Rhea-AI Filing Summary

Apolonio Arenas, a director of NSTS Bancorp, Inc., reported the disposition of 26,700 directly held common shares and 7,500 common shares held by his spouse on October 1, 2026. Under the merger terms, each outstanding common share converted into a right to receive $14.31 in cash at the merger’s effective time.

Arenas also reported cancellation of a stock option covering 23,000 shares; it converted into a cash amount based on the difference between $14.31 and its $9.36-per-share exercise price. The reported shares following each of the three transactions were 0. No Rule 10b5-1 plan is reported.

Insider Trade Summary

Tender Offer: 57,200 shares

Tender Offer 3 txns

Insider Arenas Apolonio

Role Director

Type	Security	Shares	Price	Value
Tender Offer	Stock Option F2	23,000	--	--
Tender Offer	Common Stock F1	26,700	$14.31	$382K
Tender Offer	Common Stock F1	7,500	$14.31	$107K

Holdings After Transaction: Stock Option — 0 contracts (Direct); Common Stock — 0 shares (Direct); Common Stock — 0 shares (Indirect, Held by Spouse)

Footnotes (2)

1. F1. Pursuant to the Agreement and Plan of Merger dated 05/12/2026, each outstanding share of common stock was converted into the right to receive $14.31 in cash at the effective time of the merger.
2. F2. This option, which provided for vesting in five equal annual installments beginning June 15, 2024, was cancelled in the merger and converted into the right to receive an amount in cash equal to the product of: (i) the total number of shares of Company common stock underlying the option, multiplied by (ii) the excess of (A) $14.31, over (B) the per share exercise price for such option.

Key Figures

Direct common shares disposed: 26,700 shares Spouse-held common shares disposed: 7,500 shares Merger cash consideration: $14.31 per share +3 more

6 metrics

Direct common shares disposed 26,700 shares October 1, 2026

Spouse-held common shares disposed 7,500 shares October 1, 2026

Merger cash consideration $14.31 per share Common shares converted into a right to receive cash at the merger’s effective time

Shares underlying canceled option 23,000 shares Option canceled in the merger

Option exercise price $9.36 per share Used in the option’s merger cash-conversion formula

Shares following reported transactions 0 shares Reported following each of the three transactions

Key Terms

Agreement and Plan of Merger, effective time, exercise price

3 terms

Agreement and Plan of Merger regulatory

"Agreement and Plan of Merger dated 05/12/2026"

An Agreement and Plan of Merger is a formal document where two companies agree to combine into one, outlining how the process will happen. It’s like a step-by-step plan for merging, and it matters because it shows both sides have agreed on the details before the official transition takes place.

effective time regulatory

"at the effective time of the merger"

The exact clock time when a regulatory filing, approval, or corporate action formally becomes legally active; from that moment the change is binding and can be acted on. Investors care because the effective time marks when ownership, rights, trading rules, or new securities take effect — like a light switch turning on a contract or transaction — which determines when risks, benefits and market reactions begin.

exercise price financial

"the per share exercise price for such option"

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

FAQ

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

What NSTS shares did director Apolonio Arenas dispose of?

Apolonio Arenas reported disposition of 26,700 directly held common shares and 7,500 shares held by his spouse on October 1, 2026. Both common-stock transactions carried the merger conversion right to receive $14.31 in cash per share.

How was Apolonio Arenas’s NSTS stock option handled?

The option covering 23,000 common shares was canceled in the merger and converted to cash equal to the underlying share count multiplied by the excess of $14.31 over its $9.36-per-share exercise price. It had vested in five equal annual installments beginning June 15, 2024.

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

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Available on EDGAR 10/02/2026 - 02:53 PM Accepted by SEC EDGAR 10/02/2026 - 02:53 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

X

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Arenas Apolonio

(Last) (First) (Middle)

700 S LEWIS AVE

(Street)

WAUKEGAN ILLINOIS 60085

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
NSTS Bancorp, Inc. [ NSTS ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
10/01/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	10/01/2026		U		26,700	D	$14.31(1)	0	D
Common Stock	10/01/2026		U		7,500	D	$14.31(1)	0	I	Held by Spouse

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option	$9.36	10/01/2026		U			23,000	(2)	06/15/2033	Common Stock	23,000	(2)	0	D

Explanation of Responses:

1. Pursuant to the Agreement and Plan of Merger dated 05/12/2026, each outstanding share of common stock was converted into the right to receive $14.31 in cash at the effective time of the merger.

2. This option, which provided for vesting in five equal annual installments beginning June 15, 2024, was cancelled in the merger and converted into the right to receive an amount in cash equal to the product of: (i) the total number of shares of Company common stock underlying the option, multiplied by (ii) the excess of (A) $14.31, over (B) the per share exercise price for such option.

	/s/ Carissa H. Schoolcraft, POA	10/02/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)