Ardelyx (ARDX) CEO Raab executes 54,748-share RSU tax sell-to-cover

Rhea-AI Filing Summary

ARDELYX, INC. President & CEO Michael Raab reported routine sales of company common stock tied to restricted stock unit (RSU) vesting. On May 21, 2026, entities associated with him sold a total of 54,748 shares of Ardelyx common stock at $6.2675 per share.

According to the disclosure, these transactions were an automatic sell-to-cover required by the original RSU grant terms, and the shares were sold solely to cover applicable withholding taxes at vesting. After these sales, Raab directly held about 1,759,848 common shares, with additional indirect holdings of 1,000 shares and 24,364 shares held in family-related trusts.

Insights

Equity compensation analyst

CEO’s Form 4 shows tax-driven, routine RSU-related share sales.

The filing shows Michael Raab, President & CEO of ARDELYX, INC., selling 54,748 common shares at $6.2675 per share on May 21, 2026. Footnotes state these were automatic sell-to-cover transactions linked to RSU vesting.

The footnote explains the shares were sold solely to cover withholding taxes required at vesting, indicating a mechanistic tax event rather than a discretionary portfolio decision. Following the sales, Raab still holds about 1,759,848 shares directly, plus additional indirect trust holdings, so the sale represents a small portion of his visible position.

Because the sale is both tax-driven and relatively modest versus remaining holdings, it carries limited informational value about Raab’s outlook on Ardelyx. Future compensation-related filings may provide more detail on ongoing RSU vesting patterns and associated sell-to-cover activity.

Insider Trade Summary

Net Seller: 54,748 shares ($343,133)

Net Sell 6 txns

Insider RAAB MICHAEL

Role President & CEO

Sold 54,748 shs ($343K)

Type	Security	Shares	Price	Value
Sale	Common Stock	14,933	$6.2675	$94K
Sale	Common Stock	7,861	$6.2675	$49K
Sale	Common Stock	17,926	$6.2675	$112K
Sale	Common Stock	14,028	$6.2675	$88K
holding	Common Stock	--	--	--
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 1,759,848 shares (Direct, null); Common Stock — 24,364 shares (Indirect, Family Trust)

Footnotes (1)

1. Pursuant to an automatic sell-to-cover imposed by the terms of the initial grant of the restricted stock units ("RSUs") awards, the shares were sold upon the vesting of the RSUs solely to cover applicable withholding taxes. The shares are directly held by Michael G. Raab, Trustee of the Michael G. Raab Living Trust dated July 25, 2012. The shares are owned directly by trusts for the benefit of the Reporting Person's children.

Key Figures

Shares sold: 54,748 shares Sale price: $6.2675 per share Direct holdings after sale: 1,759,848 shares +3 more

6 metrics

Shares sold 54,748 shares Total common shares sold on May 21, 2026

Sale price $6.2675 per share Price for each common share sold

Direct holdings after sale 1,759,848 shares Common shares held directly by Michael Raab after transactions

Indirect holdings (trust 1) 1,000 shares Shares held by Michael G. Raab Living Trust

Indirect holdings (trust 2) 24,364 shares Shares held by trusts for reporting person’s children

Sell transactions count 4 transactions Number of S-code open-market sale entries

Key Terms

restricted stock units ("RSUs"), automatic sell-to-cover, withholding taxes, open-market sale, +1 more

5 terms

restricted stock units ("RSUs") financial

"initial grant of the restricted stock units ("RSUs") awards, the shares were sold"

Restricted stock units (RSUs) are a company promise to give an employee shares of stock (or cash equivalent) in the future, but only after certain conditions—usually staying with the company for a set time or hitting performance goals—are met. Investors watch RSUs because when they vest they increase the number of shares outstanding and can lead insiders to sell shares, affecting share price, company dilution and the true cost of employee pay.

automatic sell-to-cover financial

"Pursuant to an automatic sell-to-cover imposed by the terms of the initial grant"

withholding taxes financial

"the shares were sold upon the vesting of the RSUs solely to cover applicable withholding taxes"

Withholding taxes are amounts a payer or government takes out of payments — such as wages, interest, or dividends — before the recipient gets the money, functioning like a cashier keeping part of a bill to pay taxes on your behalf. For investors this matters because it reduces the cash they actually receive, affects net returns and yield calculations, and may require additional paperwork or treaty claims to recover or offset the withheld amount against final tax bills.

open-market sale financial

"transaction_action": "open-market sale""

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.

Family Trust financial

""nature_of_ownership": "Family Trust""

Form 4 Insider Transactions: What Each Field Means →

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^*

RAAB MICHAEL

(Last) (First) (Middle)

C/O ARDELYX, INC.

400 FIFTH AVENUE, SUITE 210

(Street)

WALTHAM MASSACHUSETTS 02451

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/21/2026

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	05/21/2026		S(1)		14,933	D	$6.2675	1,759,848	D
Common Stock	05/21/2026		S(1)		7,861	D	$6.2675	1,751,987	D
Common Stock	05/21/2026		S(1)		17,926	D	$6.2675	1,734,061	D
Common Stock	05/21/2026		S(1)		14,028	D	$6.2675	1,720,033	D
Common Stock								24,364	I	Family Trust(2)
Common Stock								1,000	I	Family Trust(3)

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

Explanation of Responses:

1. Pursuant to an automatic sell-to-cover imposed by the terms of the initial grant of the restricted stock units ("RSUs") awards, the shares were sold upon the vesting of the RSUs solely to cover applicable withholding taxes.

2. The shares are directly held by Michael G. Raab, Trustee of the Michael G. Raab Living Trust dated July 25, 2012.

3. The shares are owned directly by trusts for the benefit of the Reporting Person's children.

Remarks:

	/s/ Michael Raab	05/22/2026
	** 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)

FAQ

What did Ardelyx (ARDX) CEO Michael Raab report in this Form 4 filing?

Michael Raab reported sales of 54,748 Ardelyx common shares at $6.2675 on May 21, 2026. Footnotes explain the sales were automatic sell-to-cover transactions tied to RSU vesting, executed solely to satisfy required tax withholding obligations.

How many Ardelyx (ARDX) shares did Michael Raab sell and at what price?

The filing shows Raab-related accounts sold a total of 54,748 Ardelyx common shares at $6.2675 per share. These sales occurred across multiple transactions on May 21, 2026, all characterized as open-market sales in the disclosure.

Were Michael Raab’s Ardelyx (ARDX) share sales discretionary or tax-related?

The sales were tax-related rather than discretionary. A footnote states an automatic sell-to-cover applied under the original RSU grant, and the shares were sold upon RSU vesting solely to cover applicable withholding taxes owed by the reporting person.

How many Ardelyx (ARDX) shares does Michael Raab hold after these transactions?

After the May 21, 2026 transactions, Raab directly holds about 1,759,848 Ardelyx common shares. The filing also reports indirect ownership of 1,000 shares and 24,364 shares through family-related trusts benefiting the reporting person and his children.

What do the family trust holdings in the Ardelyx (ARDX) Form 4 represent?

The Form 4 notes 1,000 Ardelyx shares held by the Michael G. Raab Living Trust and 24,364 shares owned by trusts for his children. These entries reflect indirect ownership, with shares legally held in trust structures associated with the reporting person’s family.

Does this Ardelyx (ARDX) Form 4 indicate any remaining derivative or option positions?

The derivative section of the summarized data is empty, indicating no derivative transactions or remaining derivative positions are shown in this particular Form 4. The reported activity relates only to common stock and RSU-driven sell-to-cover tax transactions.