Eton CBO sells 100,000 shares after option exercises

Eton Pharmaceuticals Chief Business Officer David Krempa exercised stock options and sold shares in several open-market trades.

Rhea-AI Filing Summary

Eton Pharmaceuticals Chief Business Officer David Krempa exercised stock options and sold shares in several open-market trades. On May 22–27, 2026, he exercised options to acquire 87,794 shares of common stock at exercise prices of $1.37–$3.58 per share and sold 100,000 shares in open-market transactions at weighted average prices in the low-to-mid $30s, as detailed in the filing.

Following these transactions, he holds 25,249 shares of Eton common stock directly and retains 118,406 employee stock options, according to the reported post-transaction balances.

Insider Trade Summary

Exercise and sale activity reported; no spread calculated

Exercise and Sale 15 txns

Insider Krempa David

Role Chief Business Officer

Sold 100,000 shs ($3.23M)

Approx. gross sale proceeds $3.23M

Approx. exercise cost $204K

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option	12,476	$0.00	$0.00
Exercise	Employee Stock Option	7,203	$0.00	$0.00
Exercise	Common Stock	12,476	$1.37	$17K
Exercise	Common Stock	7,203	$3.58	$26K
Sale	Common Stock	19,679	$31.4739	$619K
Exercise	Employee Stock Option	25,000	$0.00	$0.00
Exercise	Employee Stock Option	12,524	$0.00	$0.00
Exercise	Common Stock	25,000	$1.38	$35K
Exercise	Common Stock	12,524	$1.37	$17K
Sale	Common Stock	37,524	$31.4927	$1.18M
Exercise	Employee Stock Option	30,591	$0.00	$0.00
Exercise	Common Stock	30,591	$3.58	$110K
Sale	Common Stock	32,963	$33.2208	$1.10M
Sale	Common Stock	9,315	$33.8802	$316K
Sale	Common Stock	519	$35.00	$18K

Holdings After Transaction: Employee Stock Option — 118,406 contracts (Direct); Common Stock — 25,249 shares (Direct)

Footnotes (8)

1. F1. The Reporting Person will provide upon request by the Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
2. F2. The shares were sold in multiple trades at prices ranging from $33.68 to $34.66. The price reported above reflects the weighted average sales price.
3. F3. The shares were sold in multiple trades at prices ranging from $31.27 to $32.16. The price reported above reflects the weighted average sales price.
4. F4. The shares subject to the option vested in 48 equal monthly installments from the date of grant (3-12-2020) until fully vested.
5. F5. The shares were sold in multiple trades at prices ranging from $31.25 to $31.825. The price reported above reflects the weighted average sales price.
6. F6. The shares subject to the option vested annually from the date of grant (11-10-2017) in four equal installments.
7. F7. The shares were sold in multiple trades at prices ranging from $32.67 to $33.65. The price reported above reflects the weighted average sales price.
8. F8. The shares subject to option vested annually from the date of grant (8-7-2017) in four equal installments.

Key Figures

Shares sold: 100,000 shares Options exercised: 87,794 shares Post-transaction common shares: 25,249 shares +5 more

8 metrics

Shares sold 100,000 shares Total common shares sold across Form 4 period

Options exercised 87,794 shares Total common shares acquired via option exercises

Post-transaction common shares 25,249 shares Direct holdings after May 27, 2026 transactions

Remaining employee stock options 118,406 options Derivative holdings after latest option exercise

Sale price example $35.0000 per share One open-market sale on May 22, 2026

Weighted average sale price $33.2208 per share One tranche of common stock sold on May 22, 2026

Option exercise price $1.3700 per share Exercise price for certain options granted November 2017

Option exercise price $3.5800 per share Exercise price for certain options granted March 2020

Key Terms

open-market sale, Employee Stock Option, derivative security, weighted average sales price, +2 more

6 terms

open-market sale financial

"transaction_action: "open-market sale" for several common stock transactions"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Employee Stock Option financial

"security_title: "Employee Stock Option" for derivative transactions"

An employee stock option is a promise that lets a worker buy company shares later at a predetermined price, often after they stay for a certain period or meet performance goals — think of it like a coupon that locks in today's price for a future purchase. It matters to investors because options align employees’ incentives with company performance, can increase the number of shares outstanding (dilution) when exercised, and represent a compensation cost that affects reported profits and shareholder value.

derivative security financial

"transaction_code_description: "Exercise or conversion of derivative security""

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

weighted average sales price financial

"footnote: "The price reported above reflects the weighted average sales price.""

vested in 48 equal monthly installments financial

"footnote: "The shares subject to the option vested in 48 equal monthly installments""

vested annually financial

"footnote: "The shares subject to the option vested annually from the date of grant""

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

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Accepted by SEC EDGAR 05/27/2026 - 06:28 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

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^*

Krempa David

(Last) (First) (Middle)

C/O ETON PHARMACEUTICALS, INC.

21925 W. FIELD PARKWAY, SUITE 235

(Street)

DEERPARK ILLINOIS 60010-7208

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Eton Pharmaceuticals, Inc. [ ETON ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/22/2026

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	05/22/2026		M		30,591	A	$3.58	68,046	D
Common Stock	05/22/2026		S		32,963	D	$33.2208(1)(7)	35,083	D
Common Stock	05/22/2026		S		9,315	D	$33.8802(1)(2)	25,768	D
Common Stock	05/22/2026		S		519	D	$35	25,249	D
Common Stock	05/26/2026		M		25,000	A	$1.38	50,249	D
Common Stock	05/26/2026		M		12,524	A	$1.37	62,773	D
Common Stock	05/26/2026		S		37,524	D	$31.4927(1)(3)	25,249	D
Common Stock	05/27/2026		M		12,476	A	$1.37	37,725	D
Common Stock	05/27/2026		M		7,203	A	$3.58	44,928	D
Common Stock	05/27/2026		S		19,679	D	$31.4739(1)(5)	25,249	D

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
Employee Stock Option	$3.58	05/22/2026		M			30,591	03/12/2020(4)	03/11/2030	Common Stock	30,591	$0	125,609	D
Employee Stock Option	$1.38	05/26/2026		M			25,000	08/07/2017(8)	08/06/2027	Common Stock	25,000	$0	0	D
Employee Stock Option	$1.37	05/26/2026		M			12,524	11/10/2017(6)	11/09/2027	Common Stock	12,524	$0	12,476	D
Employee Stock Option	$1.37	05/27/2026		M			12,476	11/10/2017(6)	11/09/2027	Common Stock	12,476	$0	0	D
Employee Stock Option	$3.58	05/27/2026		M			7,203	03/12/2020(4)	03/11/2030	Common Stock	7,203	$0	118,406	D

Explanation of Responses:

1. The Reporting Person will provide upon request by the Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.

2. The shares were sold in multiple trades at prices ranging from $33.68 to $34.66. The price reported above reflects the weighted average sales price.

3. The shares were sold in multiple trades at prices ranging from $31.27 to $32.16. The price reported above reflects the weighted average sales price.

4. The shares subject to the option vested in 48 equal monthly installments from the date of grant (3-12-2020) until fully vested.

5. The shares were sold in multiple trades at prices ranging from $31.25 to $31.825. The price reported above reflects the weighted average sales price.

6. The shares subject to the option vested annually from the date of grant (11-10-2017) in four equal installments.

7. The shares were sold in multiple trades at prices ranging from $32.67 to $33.65. The price reported above reflects the weighted average sales price.

8. The shares subject to option vested annually from the date of grant (8-7-2017) in four equal installments.

Remarks:

The reporting person has authorized and designated the named person to file this Form 4 on the reporting person's behalf for indefinite duration.

	/s/ Judith Matthews	05/27/2026
	** 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)