Ardelyx (ARDX) CCO Eric Foster receives 137,945 RSUs and 206,915 options

Rhea-AI Filing Summary

Ardelyx, Inc. Chief Commercial Officer Eric Duane Foster reported new equity awards and updated his share holdings. On January 23, 2026, he received 137,945 shares of Common Stock for no cash consideration in the form of restricted stock units, each RSU converting into one share upon vesting. Following this grant, he beneficially owned 436,409 shares of Common Stock, which include 2,780 shares previously purchased under the Ardelyx Employee Stock Purchase Plan on August 31, 2025. He was also granted a stock option for 206,915 shares of Common Stock with a $7.77 exercise price, vesting in 48 equal monthly installments beginning on January 23, 2026, contingent on his continued employment.

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^*

Foster Eric Duane

(Last) (First) (Middle)

C/O ARDELYX, INC.

400 FIFTH AVENUE, SUITE 210

(Street)

WALTHAM MA 02451

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
ARDELYX, INC. [ ARDX ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
01/23/2026

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

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

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

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	01/23/2026		A		137,945(1)	A	$0	436,409(2)	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
Stock Option (Right to Buy)	$7.77	01/23/2026		A		206,915		(3)	01/23/2036	Common Stock	206,915	$0	206,915	D

Explanation of Responses:

1. Restricted stock units ("RSUs"). The Reporting Person is entitled to receive one (1) shares of Common Stock for each one (1) RSU upon the vesting thereof.

2. Includes the purchase of 2,780 shares under the Ardelyx Employee Stock Purchase Plan on August 31, 2025.

3. The option becomes exercisable as it vests and the shares subject to the option vest in 48 successive, equal monthly installments on each monthly anniversary of January 23, 2026, subject to the Reporting Person's continued employment or service relationship with the Issuer on each such vesting date.

	/s/ Elizabeth Grammer, Attorney-in-fact for Eric D. Foster	01/26/2026
	** 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.

FAQ

What insider transaction did Ardelyx (ARDX) report for Eric Duane Foster?

Ardelyx reported that Chief Commercial Officer Eric Duane Foster received 137,945 shares of Common Stock on January 23, 2026 for no cash consideration in the form of restricted stock units that convert to shares upon vesting.

How many Ardelyx (ARDX) shares does Eric Duane Foster own after this Form 4?

After the reported transaction, Eric Duane Foster beneficially owned 436,409 shares of Ardelyx Common Stock, including 2,780 shares acquired through the Ardelyx Employee Stock Purchase Plan on August 31, 2025.

What stock options were granted to Eric Duane Foster in Ardelyx (ARDX)?

On January 23, 2026, Foster was granted a stock option for 206,915 shares of Ardelyx Common Stock with a $7.77 exercise price per share. The option was granted at no cost to him.

How do Eric Duane Foster’s Ardelyx (ARDX) stock options vest?

The 206,915-share stock option vests as it becomes exercisable in 48 successive, equal monthly installments on each monthly anniversary of January 23, 2026, subject to his continued employment or service relationship with Ardelyx on each vesting date.

What are the terms of the restricted stock units granted to Eric Duane Foster at Ardelyx (ARDX)?

The grant consists of restricted stock units (RSUs) under which Eric Duane Foster is entitled to receive one share of Common Stock for each RSU upon vesting, with no cash price paid for the shares at vesting.

Is Eric Duane Foster a director or major shareholder of Ardelyx (ARDX)?

In this filing, Eric Duane Foster is identified as an officer of Ardelyx with the title Chief Commercial Officer, and he is not listed as a director or 10% owner.