Ardelyx, Inc.
US ˙ NasdaqGM ˙ US0396971071

SecurityARDX / Ardelyx, Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership3,464,774 shares
Latest Disclosed Value $ 20,753,997
Citadel Advisors Llc ownership in ARDX / Ardelyx, Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 3,464,774 shares of Ardelyx, Inc. (US:ARDX) valued at $20,753,996 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 1,327,453 shares of Ardelyx, Inc.. This represents a change in shares of 161.01% during the quarter. The current value of the position is $19,264,143 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (ARDX) in the form of stock options. The firm currently holds call options representing 127,000 of underlying shares valued at $760,730 USD and put options representing 172,000 of underlying shares valued at $1,030,280 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

ARDX / Ardelyx, Inc. Historical Put/Call Ratio
Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date
Effective
Date
Form Security Class ID Avg Price
Paid (Est)
Reported
Shares
ΔShares ΔShares
(%)
Reported
Value
(x1000)
ΔValue
(%)
Alloc
(%)
ΔAlloc ΔAlloc (%) Cost Basis
(x1000)
Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F ARDELYX COM 039697107 3,464,774 2,137,321 161.01 20,754 168.16 0.0030
2026-02-17 2025-12-31 13F ARDELYX COM 039697107 1,327,453 -201,079 -13.16 7,739 -8.11 0.0012
2025-11-14 2025-09-30 13F ARDELYX COM 039697107 1,528,532 -682,728 -30.88 8,422 -2.84 0.0013
2025-08-14 2025-06-30 13F ARDELYX COM 039697107 2,211,260 -979,095 -30.69 8,668 -44.66 0.0015
2025-05-15 2025-03-31 13F ARDELYX COM 039697107 3,190,355 699,737 28.09 15,665 24.05 0.0030
2025-02-14 2024-12-31 13F ARDELYX COM 039697107 2,490,618 281,685 12.75 12,627 -17.03 0.0022
2024-11-14 2024-09-30 13F ARDELYX COM 039697107 2,208,933 1,948,301 747.53 15,220 688.14 0.0029
2024-08-14 2024-06-30 13F ARDELYX COM 039697107 260,632 -190,073 -42.17 1,931 -41.31 0.0004
2024-05-15 2024-03-31 13F ARDELYX COM 039697107 450,705 284,402 171.01 3,290 219.11 0.0006
2024-02-14 2023-12-31 13F ARDELYX COM 039697107 166,303 -48,887 -22.72 1,031 17.56 0.0002
2023-11-14 2023-09-30 13F ARDELYX COM 039697107 215,190 147,223 216.61 878 281.30 0.0002
2023-08-14 2023-06-30 13F ARDELYX COM 039697107 67,967 -182,519 -72.87 230 -80.82 0.0000
2023-05-15 2023-03-31 13F ARDELYX COM 039697107 250,486 241,300 2,626.82 1,200 4,511.54 0.0003
2023-02-14 2022-12-31 13F ARDELYX COM 039697107 9,186 -116,345 -92.68 26 -82.67 0.0000
2022-11-14 2022-09-30 13F ARDELYX COM 039697107 125,531 -311,035 -71.25 150 -41.86 0.0000
2022-08-15 2022-06-30 13F ARDELYX COM 039697107 436,566 436,566 258 0.0001
2022-05-16 2022-03-31 13F ARDELYX COM 039697107 0 -179,343 -100.00 0 -100.00
2022-02-14 2021-12-31 13F ARDELYX COM 039697107 179,343 -34,010 -15.94 197 -30.14 0.0000
2021-11-15 2021-09-30 13F ARDELYX Cmn 039697107 213,353 89,580 72.37 282 -69.94 0.0001
2021-08-16 2021-06-30 13F ARDELYX COM 039697107 123,773 69,129 126.51 938 159.12 0.0002
2021-05-21 2021-03-31 13F/A-1 ARDELYX COM 039697107 54,644 -19,982 -26.78 362 -25.05 0.0001
2021-05-17 2021-03-31 13F ARDELYX COM 039697107 54,644 -19,982 362 0.0001
2021-02-16 2020-12-31 13F ARDELYX COM 039697107 74,626 24,584 49.13 483 84.35 0.0001
2020-11-16 2020-09-30 13F ARDELYX COM 039697107 50,042 50,042 -32.94 262 -45.76 0.0001
2020-08-14 2020-06-30 13F ARDELYX Cmn 039697107 0 -198,674 -100.00 0 -100.00
2020-05-15 2020-03-31 13F ARDELYX Cmn 039697107 198,674 61,617 44.96 1,129 9.82 0.0005
2020-02-14 2019-12-31 13F ARDELYX Cmn 039697107 137,057 117,217 590.81 1,028 1,005.38 0.0004
2019-11-14 2019-09-30 13F ARDELYX Cmn 039697107 19,840 5,967 43.01 93 151.35 0.0000
2019-08-14 2019-06-30 13F ARDELYX Cmn 039697107 13,873 13,873 -30.08 37 -60.22 0.0000
2019-05-15 2019-03-31 13F ARDELYX Cmn 039697107 0 -59,210 -100.00 0 -100.00
2019-02-14 2018-12-31 13F ARDELYX Cmn 039697107 59,210 10,830 22.39 106 -49.76 0.0001
2018-11-13 2018-09-30 13F ARDELYX Cmn 039697107 48,380 15,637 47.76 211 74.38 0.0001
2018-08-14 2018-06-30 13F/A-1 ARDELYX Cmn 039697107 32,743 5,076 18.35 121 -13.57 0.0001
2018-08-10 2018-06-30 13F ARDELYX Cmn 039697107 32,743 5,076 121
2018-05-14 2018-03-31 13F/A-1 ARDELYX Cmn 039697107 27,667 -3,435 -11.04 140 -31.71 0.0001
2018-05-11 2018-03-31 13F ARDELYX Cmn 039697107 27,667 -3,435 140
2018-02-09 2017-12-31 13F ARDELYX Cmn 039697107 31,102 -27,424 -46.86 205 -37.50 0.0001
2017-11-09 2017-09-30 13F ARDELYX Cmn 039697107 58,526 9,986 20.57 328 32.26 0.0003
2017-08-11 2017-06-30 13F ARDELYX Cmn 039697107 48,540 48,540 -17.06 248 -24.39 0.0002
2017-05-12 2017-03-31 13F ARDELYX Cmn 039697107 0 -14,620 -100.00 0 -100.00
2017-02-10 2016-12-31 13F ARDELYX Cmn 039697107 14,620 4,301 41.68 208 55.22 0.0002
2017-01-31 2016-09-30 13F/A-1 ARDELYX Cmn 039697107 10,319 10,319 134 0.0001
2016-11-10 2016-09-30 13F ARDELYX Cmn 039697107 10,319 134 0.0001
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F ARDELYX COM Call 127,000 -42.30 761 -40.76 n/a n/a n/a
2026-02-17 2025-12-31 13F ARDELYX COM Call 220,100 18.33 1,283 25.29 n/a n/a n/a
2025-11-14 2025-09-30 13F ARDELYX COM Call 186,000 -2.31 1,025 37.27 n/a n/a n/a
2025-08-14 2025-06-30 13F ARDELYX COM Call 190,400 16.52 746 -6.98 n/a n/a n/a
2025-05-15 2025-03-31 13F ARDELYX COM Call 163,400 -27.99 802 -30.26 n/a n/a n/a
2025-02-14 2024-12-31 13F ARDELYX COM Call 226,900 -33.42 1,150 -51.02 n/a n/a n/a
2024-11-14 2024-09-30 13F ARDELYX COM Call 340,800 76.03 2,348 63.74 n/a n/a n/a
2024-08-14 2024-06-30 13F ARDELYX COM Call 193,600 -25.08 1,435 -23.97 n/a n/a n/a
2024-05-15 2024-03-31 13F ARDELYX COM Call 258,400 -19.12 1,886 -4.75 n/a n/a n/a
2024-02-14 2023-12-31 13F ARDELYX COM Call 319,500 172.15 1,981 314.23 n/a n/a n/a
2023-11-14 2023-09-30 13F ARDELYX COM Call 117,400 -41.79 479 -30.01 n/a n/a n/a
2023-08-14 2023-06-30 13F ARDELYX COM Call 201,700 -26.49 684 -48.02 n/a n/a n/a
2023-05-15 2023-03-31 13F ARDELYX COM Call 274,400 -25.66 1,314 25.02 n/a n/a n/a
2023-02-14 2022-12-31 13F ARDELYX COM Call 369,100 43.56 1,052 243.46 n/a n/a n/a
2022-11-14 2022-09-30 13F ARDELYX COM Call 257,100 79.04 306 260.00 n/a n/a n/a
2022-08-15 2022-06-30 13F ARDELYX COM Call 143,600 13.52 85 -37.04 n/a n/a n/a
2022-05-16 2022-03-31 13F ARDELYX COM Call 126,500 -27.42 135 -29.69 n/a n/a n/a
2022-02-14 2021-12-31 13F ARDELYX COM Call 174,300 718.31 192 585.71 n/a n/a n/a
2021-11-15 2021-09-30 13F ARDELYX Cmn Call 21,300 -44.96 28 -90.44 n/a n/a n/a
2021-08-16 2021-06-30 13F ARDELYX COM Call 38,700 -32.34 293 -22.69 n/a n/a n/a
2021-05-21 2021-03-31 13F/A ARDELYX COM Call 57,200 145.49 379 150.99 n/a n/a n/a
2021-05-17 2021-03-31 13F ARDELYX COM Call 57,200 379 n/a n/a n/a
2021-02-16 2020-12-31 13F ARDELYX COM Call 23,300 -59.27 151 -60.16 n/a n/a n/a
2020-02-14 2019-12-31 13F ARDELYX Cmn Call 0 -100.00 0 -100.00 n/a n/a n/a
2019-11-14 2019-09-30 13F ARDELYX Cmn Call 14,500 68 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F ARDELYX COM Put 172,000 -25.80 1,030 -23.76 n/a n/a n/a
2026-02-17 2025-12-31 13F ARDELYX COM Put 231,800 -39.59 1,351 -36.09 n/a n/a n/a
2025-11-14 2025-09-30 13F ARDELYX COM Put 383,700 -19.32 2,114 13.41 n/a n/a n/a
2025-08-14 2025-06-30 13F ARDELYX COM Put 475,600 6.14 1,864 -15.27 n/a n/a n/a
2025-05-15 2025-03-31 13F ARDELYX COM Put 448,100 -17.13 2,200 -19.74 n/a n/a n/a
2025-02-14 2024-12-31 13F ARDELYX COM Put 540,700 11.05 2,741 -18.28 n/a n/a n/a
2024-11-14 2024-09-30 13F ARDELYX COM Put 486,900 -0.47 3,355 -7.45 n/a n/a n/a
2024-08-14 2024-06-30 13F ARDELYX COM Put 489,200 36.65 3,625 38.69 n/a n/a n/a
2024-05-15 2024-03-31 13F ARDELYX COM Put 358,000 21.69 2,613 43.26 n/a n/a n/a
2024-02-14 2023-12-31 13F ARDELYX COM Put 294,200 -3.29 1,824 46.98 n/a n/a n/a
2023-11-14 2023-09-30 13F ARDELYX COM Put 304,200 30.61 1,241 57.29 n/a n/a n/a
2023-08-14 2023-06-30 13F ARDELYX COM Put 232,900 -22.00 790 -44.83 n/a n/a n/a
2023-05-15 2023-03-31 13F ARDELYX COM Put 298,600 -37.82 1,430 4.53 n/a n/a n/a
2023-02-14 2022-12-31 13F ARDELYX COM Put 480,200 574.44 1,369 1,509.41 n/a n/a n/a
2022-11-14 2022-09-30 13F ARDELYX COM Put 71,200 46.20 85 193.10 n/a n/a n/a
2022-08-15 2022-06-30 13F ARDELYX COM Put 48,700 -40.25 29 -66.67 n/a n/a n/a
2022-05-16 2022-03-31 13F ARDELYX COM Put 81,500 -57.55 87 -58.77 n/a n/a n/a
2022-02-14 2021-12-31 13F ARDELYX COM Put 192,000 15.52 211 -3.65 n/a n/a n/a
2021-11-15 2021-09-30 13F ARDELYX Cmn Put 166,200 84.87 219 -67.84 n/a n/a n/a
2021-08-16 2021-06-30 13F ARDELYX COM Put 89,900 68.04 681 92.37 n/a n/a n/a
2021-05-21 2021-03-31 13F/A ARDELYX COM Put 53,500 110.63 354 115.85 n/a n/a n/a
2021-05-17 2021-03-31 13F ARDELYX COM Put 53,500 354 n/a n/a n/a
2021-02-16 2020-12-31 13F ARDELYX COM Put 25,400 9.48 164 34.43 n/a n/a n/a
2020-11-16 2020-09-30 13F ARDELYX COM Put 23,200 58.90 122 20.79 n/a n/a n/a
2020-08-14 2020-06-30 13F ARDELYX Cmn Put 14,600 -37.07 101 -23.48 n/a n/a n/a
2020-05-15 2020-03-31 13F ARDELYX Cmn Put 23,200 4.50 132 -20.96 n/a n/a n/a
2020-02-14 2019-12-31 13F ARDELYX Cmn Put 22,200 12.12 167 79.57 n/a n/a n/a
2019-11-14 2019-09-30 13F ARDELYX Cmn Put 19,800 -10.81 93 -44.31 n/a n/a n/a
2019-05-15 2019-03-31 13F ARDELYX Cmn Put 0 -100.00 0 -100.00 n/a n/a n/a
2019-02-14 2018-12-31 13F ARDELYX Cmn Put 17,200 -26.50 31 -69.61 n/a n/a n/a
2018-11-13 2018-09-30 13F ARDELYX Cmn Put 23,400 -13.97 102 0.99 n/a n/a n/a
2018-08-14 2018-06-30 13F/A ARDELYX Cmn Put 27,200 147.27 101 80.36 n/a n/a n/a
2018-08-10 2018-06-30 13F ARDELYX Cmn Put 27,200 101 n/a n/a n/a
2018-05-14 2018-03-31 13F/A ARDELYX Cmn Put 11,000 56 n/a n/a n/a
2018-05-11 2018-03-31 13F ARDELYX Cmn Put 11,000 56 n/a n/a n/a
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.