Syndax Pharmaceuticals, Inc.
US ˙ NasdaqGS ˙ US87164F1057

SecuritySNDX / Syndax Pharmaceuticals, Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership630,942 shares
Latest Disclosed Value $ 14,738,805
Citadel Advisors Llc ownership in SNDX / Syndax Pharmaceuticals, Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 630,942 shares of Syndax Pharmaceuticals, Inc. (US:SNDX) valued at $14,738,805 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 184,003 shares of Syndax Pharmaceuticals, Inc.. This represents a change in shares of 242.90% during the quarter. The current value of the position is $10,940,534 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (SNDX) in the form of stock options. The firm currently holds call options representing 72,400 of underlying shares valued at $1,691,264 USD and put options representing 64,200 of underlying shares valued at $1,499,712 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.

SNDX / Syndax Pharmaceuticals, 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 SYNDAX PHARMACEUTICALS COM 87164F105 630,942 446,939 242.90 14,739 281.32 0.0024
2026-02-17 2025-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 184,003 -362,265 -66.32 3,866 -54.01 0.0006
2025-11-14 2025-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 546,268 -93,732 -14.65 8,404 40.23 0.0013
2025-08-14 2025-06-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 640,000 -2,274,882 -78.04 5,994 -83.26 0.0010
2025-05-15 2025-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 2,914,882 1,825,079 167.47 35,809 148.55 0.0068
2025-02-14 2024-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 1,089,803 1,055,783 3,103.42 14,407 2,102.91 0.0025
2024-11-14 2024-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 34,020 -155,961 -82.09 655 -83.23 0.0001
2024-08-14 2024-06-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 189,981 156,172 461.92 3,900 385.07 0.0008
2024-05-15 2024-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 33,809 -209,176 -86.09 805 -84.69 0.0002
2024-02-14 2023-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 242,985 -192,508 -44.20 5,251 -16.97 0.0010
2023-11-14 2023-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 435,493 198,543 83.79 6,323 27.51 0.0014
2023-08-14 2023-06-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 236,950 -1,342,719 -85.00 4,959 -85.14 0.0010
2023-05-15 2023-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 1,579,669 -48,184 -2.96 33,363 -19.47 0.0073
2023-02-14 2022-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 1,627,853 261,082 19.10 41,429 26.14 0.0097
2022-11-14 2022-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 1,366,771 -362,281 -20.95 32,844 -1.27 0.0075
2022-08-15 2022-06-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 1,729,052 -96,388 -5.28 33,267 4.86 0.0085
2022-05-16 2022-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 1,825,440 -193,387 -9.58 31,726 -28.21 0.0065
2022-02-14 2021-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 2,018,827 175,470 9.52 44,192 25.45 0.0090
2021-11-15 2021-09-30 13F SYNDAX PHARMACEUTICALS Cmn 87164F105 1,843,357 -115,274 -5.89 35,226 4.75 0.0073
2021-08-16 2021-06-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 1,958,631 -271,492 -12.17 33,630 -32.56 0.0075
2021-05-21 2021-03-31 13F/A-1 SYNDAX PHARMACEUTICALS COM 87164F105 2,230,123 118,605 5.62 49,866 6.19 0.0122
2021-05-17 2021-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 2,230,123 118,605 49,866 0.0122
2021-02-16 2020-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 2,111,518 1,549,104 275.44 46,960 465.71 0.0122
2020-11-16 2020-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 562,414 -479,166 -46.00 8,301 -46.22 0.0024
2020-08-14 2020-06-30 13F SYNDAX PHARMACEUTICALS Cmn 87164F105 1,041,580 1,028,435 7,823.77 15,436 10,619.44 0.0055
2020-05-15 2020-03-31 13F SYNDAX PHARMACEUTICALS Cmn 87164F105 13,145 -9,053 -40.78 144 -26.15 0.0001
2020-02-14 2019-12-31 13F SYNDAX PHARMACEUTICALS Cmn 87164F105 22,198 22,198 195 0.0001
2019-05-15 2019-03-31 13F SYNDAX PHARMACEUTICALS Cmn 87164F105 0 -35,007 -100.00 0 -100.00
2019-02-14 2018-12-31 13F SYNDAX PHARMACEUTICALS Cmn 87164F105 35,007 -23,048 -39.70 156 -66.74 0.0001
2018-11-13 2018-09-30 13F SYNDAX PHARMACEUTICALS Cmn 87164F105 58,055 35,557 158.05 469 196.84 0.0002
2018-08-14 2018-06-30 13F/A-1 SYNDAX PHARMACEUTICALS Cmn 87164F105 22,498 22,498 158 0.0001
2018-08-10 2018-06-30 13F SYNDAX PHARMACEUTICALS Cmn 87164F105 22,498 158 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 SYNDAX PHARMACEUTICALS COM Call 72,400 -47.23 1,691 -41.33 n/a n/a n/a
2026-02-17 2025-12-31 13F SYNDAX PHARMACEUTICALS COM Call 137,200 27.51 2,883 74.14 n/a n/a n/a
2025-11-14 2025-09-30 13F SYNDAX PHARMACEUTICALS COM Call 107,600 36.55 1,655 124.56 n/a n/a n/a
2025-08-14 2025-06-30 13F SYNDAX PHARMACEUTICALS COM Call 78,800 -9.22 738 -30.86 n/a n/a n/a
2025-05-15 2025-03-31 13F SYNDAX PHARMACEUTICALS COM Call 86,800 -31.60 1,066 -36.43 n/a n/a n/a
2025-02-14 2024-12-31 13F SYNDAX PHARMACEUTICALS COM Call 126,900 233.95 1,678 129.41 n/a n/a n/a
2024-11-14 2024-09-30 13F SYNDAX PHARMACEUTICALS COM Call 38,000 52.00 732 42.50 n/a n/a n/a
2024-08-14 2024-06-30 13F SYNDAX PHARMACEUTICALS COM Call 25,000 -34.38 513 -43.38 n/a n/a n/a
2024-05-15 2024-03-31 13F SYNDAX PHARMACEUTICALS COM Call 38,100 -1.30 907 8.63 n/a n/a n/a
2024-02-14 2023-12-31 13F SYNDAX PHARMACEUTICALS COM Call 38,600 -75.98 834 -64.25 n/a n/a n/a
2023-11-14 2023-09-30 13F SYNDAX PHARMACEUTICALS COM Call 160,700 11,378.57 2,333 7,944.83 n/a n/a n/a
2023-08-14 2023-06-30 13F SYNDAX PHARMACEUTICALS COM Call 1,400 -53.33 29 -53.97 n/a n/a n/a
2023-05-15 2023-03-31 13F SYNDAX PHARMACEUTICALS COM Call 3,000 -93.88 63 -94.95 n/a n/a n/a
2023-02-14 2022-12-31 13F SYNDAX PHARMACEUTICALS COM Call 49,000 -46.68 1,247 -43.52 n/a n/a n/a
2022-11-14 2022-09-30 13F SYNDAX PHARMACEUTICALS COM Call 91,900 -5.55 2,208 17.95 n/a n/a n/a
2022-08-15 2022-06-30 13F SYNDAX PHARMACEUTICALS COM Call 97,300 83.24 1,872 102.82 n/a n/a n/a
2022-05-16 2022-03-31 13F SYNDAX PHARMACEUTICALS COM Call 53,100 361.74 923 266.27 n/a n/a n/a
2022-02-14 2021-12-31 13F SYNDAX PHARMACEUTICALS COM Call 11,500 -33.53 252 -23.87 n/a n/a n/a
2021-11-15 2021-09-30 13F SYNDAX PHARMACEUTICALS Cmn Call 17,300 -52.08 331 -46.61 n/a n/a n/a
2021-08-16 2021-06-30 13F SYNDAX PHARMACEUTICALS COM Call 36,100 211.21 620 139.38 n/a n/a n/a
2021-05-21 2021-03-31 13F/A SYNDAX PHARMACEUTICALS COM Call 11,600 -34.09 259 -33.76 n/a n/a n/a
2021-05-17 2021-03-31 13F SYNDAX PHARMACEUTICALS COM Call 11,600 259 n/a n/a n/a
2021-02-16 2020-12-31 13F SYNDAX PHARMACEUTICALS COM Call 17,600 -43.04 391 -14.25 n/a n/a n/a
2020-11-16 2020-09-30 13F SYNDAX PHARMACEUTICALS COM Call 30,900 -41.14 456 -41.39 n/a n/a n/a
2020-08-14 2020-06-30 13F SYNDAX PHARMACEUTICALS Cmn Call 52,500 102.70 778 173.94 n/a n/a n/a
2020-05-15 2020-03-31 13F SYNDAX PHARMACEUTICALS Cmn Call 25,900 96.21 284 144.83 n/a n/a n/a
2020-02-14 2019-12-31 13F SYNDAX PHARMACEUTICALS Cmn Call 13,200 10.00 116 28.89 n/a n/a n/a
2019-11-14 2019-09-30 13F SYNDAX PHARMACEUTICALS Cmn Call 12,000 -7.69 90 -25.62 n/a n/a n/a
2019-08-14 2019-06-30 13F SYNDAX PHARMACEUTICALS Cmn Call 13,000 -36.59 121 12.04 n/a n/a n/a
2019-05-15 2019-03-31 13F SYNDAX PHARMACEUTICALS Cmn Call 20,500 -38.07 108 -26.53 n/a n/a n/a
2019-02-14 2018-12-31 13F SYNDAX PHARMACEUTICALS Cmn Call 33,100 147 n/a n/a n/a
2018-11-13 2018-09-30 13F SYNDAX PHARMACEUTICALS Cmn Call 0 -100.00 0 -100.00 n/a n/a n/a
2018-08-14 2018-06-30 13F/A SYNDAX PHARMACEUTICALS Cmn Call 10,400 73 n/a n/a n/a
2018-08-10 2018-06-30 13F SYNDAX PHARMACEUTICALS Cmn Call 10,400 73 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 SYNDAX PHARMACEUTICALS COM Put 64,200 36.31 1,500 51.57 n/a n/a n/a
2026-02-17 2025-12-31 13F SYNDAX PHARMACEUTICALS COM Put 47,100 -31.84 990 -6.96 n/a n/a n/a
2025-11-14 2025-09-30 13F SYNDAX PHARMACEUTICALS COM Put 69,100 27.73 1,063 110.08 n/a n/a n/a
2025-08-14 2025-06-30 13F SYNDAX PHARMACEUTICALS COM Put 54,100 173.23 507 108.23 n/a n/a n/a
2025-05-15 2025-03-31 13F SYNDAX PHARMACEUTICALS COM Put 19,800 -52.06 243 -55.41 n/a n/a n/a
2025-02-14 2024-12-31 13F SYNDAX PHARMACEUTICALS COM Put 41,300 -23.23 546 -47.34 n/a n/a n/a
2024-11-14 2024-09-30 13F SYNDAX PHARMACEUTICALS COM Put 53,800 72.99 1,036 62.23 n/a n/a n/a
2024-08-14 2024-06-30 13F SYNDAX PHARMACEUTICALS COM Put 31,100 -42.09 638 -50.08 n/a n/a n/a
2024-05-15 2024-03-31 13F SYNDAX PHARMACEUTICALS COM Put 53,700 -59.87 1,278 -55.79 n/a n/a n/a
2024-02-14 2023-12-31 13F SYNDAX PHARMACEUTICALS COM Put 133,800 -57.98 2,891 -37.46 n/a n/a n/a
2023-11-14 2023-09-30 13F SYNDAX PHARMACEUTICALS COM Put 318,400 10,513.33 4,623 7,356.45 n/a n/a n/a
2023-08-14 2023-06-30 13F SYNDAX PHARMACEUTICALS COM Put 3,000 -81.25 63 -81.60 n/a n/a n/a
2023-05-15 2023-03-31 13F SYNDAX PHARMACEUTICALS COM Put 16,000 -1.23 338 -18.20 n/a n/a n/a
2023-02-14 2022-12-31 13F SYNDAX PHARMACEUTICALS COM Put 16,200 412 n/a n/a n/a
2022-03-11 2021-09-30 13F/A SYNDAX PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-11-15 2021-09-30 13F SYNDAX PHARMACEUTICALS COM Put 0 0 n/a n/a n/a
2021-08-16 2021-06-30 13F SYNDAX PHARMACEUTICALS COM Put 42,200 -37.57 725 -52.05 n/a n/a n/a
2021-05-21 2021-03-31 13F/A SYNDAX PHARMACEUTICALS COM Put 67,600 8.86 1,512 9.49 n/a n/a n/a
2021-05-17 2021-03-31 13F SYNDAX PHARMACEUTICALS COM Put 67,600 1,512 n/a n/a n/a
2021-02-16 2020-12-31 13F SYNDAX PHARMACEUTICALS COM Put 62,100 430.77 1,381 698.27 n/a n/a n/a
2020-11-16 2020-09-30 13F SYNDAX PHARMACEUTICALS COM Put 11,700 -6.40 173 -6.49 n/a n/a n/a
2020-08-14 2020-06-30 13F SYNDAX PHARMACEUTICALS Cmn Put 12,500 185 n/a n/a n/a
2020-05-15 2020-03-31 13F SYNDAX PHARMACEUTICALS Cmn Put 0 -100.00 0 -100.00 n/a n/a n/a
2020-02-14 2019-12-31 13F SYNDAX PHARMACEUTICALS Cmn Put 17,700 -78.80 155 -75.16 n/a n/a n/a
2019-11-14 2019-09-30 13F SYNDAX PHARMACEUTICALS Cmn Put 83,500 624 n/a n/a n/a
2019-05-15 2019-03-31 13F SYNDAX PHARMACEUTICALS Cmn Put 0 -100.00 0 -100.00 n/a n/a n/a
2019-02-14 2018-12-31 13F SYNDAX PHARMACEUTICALS Cmn Put 44,500 125.89 198 24.53 n/a n/a n/a
2018-11-13 2018-09-30 13F SYNDAX PHARMACEUTICALS Cmn Put 19,700 16.57 159 33.61 n/a n/a n/a
2018-08-14 2018-06-30 13F/A SYNDAX PHARMACEUTICALS Cmn Put 16,900 119 n/a n/a n/a
2018-08-10 2018-06-30 13F SYNDAX PHARMACEUTICALS Cmn Put 16,900 119 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.