Syndax Pharmaceuticals, Inc.
US ˙ NasdaqGS ˙ US87164F1057

SecuritySNDX / Syndax Pharmaceuticals, Inc.
InstitutionCaption Management, LLC
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Caption Management, LLC ownership in SNDX / Syndax Pharmaceuticals, Inc.

On November 14, 2025 - Caption Management, LLC filed a 13F-HR form disclosing ownership of 0 shares of Syndax Pharmaceuticals, Inc. (US:SNDX) valued at $0 USD as of September 30, 2025. The entity filed a previous 13F-HR on August 14, 2025 disclosing 504,471 shares of Syndax Pharmaceuticals, Inc.. This represents a change in shares of -100.00% during the quarter. The current value of the position is $0 USD.

Caption Management, 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 0 of underlying shares valued at $0 USD and put options representing 0 of underlying shares valued at $0 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)
2025-11-14 2025-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 0 -504,471 -100.00 0 -100.00
2025-08-14 2025-06-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 504,471 322,571 177.33 4,724 111.46 0.0523
2025-05-15 2025-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 181,900 -32,767 -15.26 2,235 -21.25 0.0215
2025-02-14 2024-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 214,667 194,341 956.12 2,838 625.58 0.0268
2024-11-14 2024-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 20,326 20,326 391 0.0062
2024-02-14 2023-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 0 -9,302 -100.00 0 -100.00
2023-11-14 2023-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 9,302 -2,498 -21.17 135 -45.12 0.0021
2023-08-14 2023-06-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 11,800 -3,200 -21.33 247 -22.15 0.0044
2023-05-15 2023-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 15,000 15,000 317 0.0061
2022-05-13 2022-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 0 -46,226 -100.00 0 -100.00
2022-02-11 2021-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 46,226 46,226 1,012 0.0113
2021-11-12 2021-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 0 -19,629 -100.00 0 -100.00
2021-08-16 2021-06-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 19,629 -33,371 -62.96 337 -71.56 0.0044
2021-05-17 2021-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 53,000 20,000 60.61 1,185 61.66 0.0255
2021-02-16 2020-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 33,000 21,886 196.92 733 346.95 0.0167
2020-11-16 2020-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 11,114 11,114 164 0.0038
2020-02-13 2019-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 0 -500 -100.00 0 -100.00
2019-11-14 2019-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 500 500 4 0.0002
2019-05-14 2019-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 0 -84,666 -100.00 0 -100.00
2019-01-30 2018-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 84,666 32,666 62.82 377 -10.45 0.0301
2018-11-14 2018-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 52,000 52,000 421 0.0232
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 0 -100.00 0 n/a n/a n/a
2026-02-17 2025-12-31 13F SYNDAX PHARMACEUTICALS COM Call 424,500 -31.40 8,919 -6.32 n/a n/a n/a
2025-11-14 2025-09-30 13F SYNDAX PHARMACEUTICALS COM Call 618,800 26.57 9,520 107.95 n/a n/a n/a
2025-08-14 2025-06-30 13F SYNDAX PHARMACEUTICALS COM Call 488,900 95.56 4,579 49.07 n/a n/a n/a
2025-05-15 2025-03-31 13F SYNDAX PHARMACEUTICALS COM Call 250,000 102.76 3,071 88.40 n/a n/a n/a
2025-02-14 2024-12-31 13F SYNDAX PHARMACEUTICALS COM Call 123,300 -2.30 1,630 -32.89 n/a n/a n/a
2024-11-14 2024-09-30 13F SYNDAX PHARMACEUTICALS COM Call 126,200 2,429 n/a n/a n/a
2024-05-15 2024-03-31 13F SYNDAX PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2024-02-14 2023-12-31 13F SYNDAX PHARMACEUTICALS COM Call 39,900 -96.92 862 -95.42 n/a n/a n/a
2023-11-14 2023-09-30 13F SYNDAX PHARMACEUTICALS COM Call 1,295,300 4,217.67 18,808 2,899.52 n/a n/a n/a
2023-08-14 2023-06-30 13F SYNDAX PHARMACEUTICALS COM Call 30,000 -50.00 628 -50.51 n/a n/a n/a
2023-05-15 2023-03-31 13F SYNDAX PHARMACEUTICALS COM Call 60,000 1,267 n/a n/a n/a
2021-05-17 2021-03-31 13F SYNDAX PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-02-16 2020-12-31 13F SYNDAX PHARMACEUTICALS COM Call 15,700 349 n/a n/a n/a
2020-11-16 2020-09-30 13F SYNDAX PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2020-08-14 2020-06-30 13F SYNDAX PHARMACEUTICALS COM Call 224,700 -0.66 3,330 34.17 n/a n/a n/a
2020-05-15 2020-03-31 13F SYNDAX PHARMACEUTICALS COM Call 226,200 18.06 2,482 47.56 n/a n/a n/a
2020-02-13 2019-12-31 13F SYNDAX PHARMACEUTICALS COM Call 191,600 283.20 1,682 349.73 n/a n/a n/a
2019-11-14 2019-09-30 13F SYNDAX PHARMACEUTICALS COM Call 50,000 374 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 0 -100.00 0 n/a n/a n/a
2026-02-17 2025-12-31 13F SYNDAX PHARMACEUTICALS COM Put 130,000 -13.33 2,731 18.38 n/a n/a n/a
2025-11-14 2025-09-30 13F SYNDAX PHARMACEUTICALS COM Put 150,000 -80.55 2,308 -68.06 n/a n/a n/a
2025-08-14 2025-06-30 13F SYNDAX PHARMACEUTICALS COM Put 771,400 208.56 7,224 135.23 n/a n/a n/a
2025-05-15 2025-03-31 13F SYNDAX PHARMACEUTICALS COM Put 250,000 -30.42 3,071 -35.33 n/a n/a n/a
2025-02-14 2024-12-31 13F SYNDAX PHARMACEUTICALS COM Put 359,300 37.29 4,750 -5.72 n/a n/a n/a
2024-11-14 2024-09-30 13F SYNDAX PHARMACEUTICALS COM Put 261,700 5,038 n/a n/a n/a
2024-05-15 2024-03-31 13F SYNDAX PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-02-14 2023-12-31 13F SYNDAX PHARMACEUTICALS COM Put 39,900 -90.74 862 -86.22 n/a n/a n/a
2023-11-14 2023-09-30 13F SYNDAX PHARMACEUTICALS COM Put 430,800 1,336.00 6,255 897.61 n/a n/a n/a
2023-08-14 2023-06-30 13F SYNDAX PHARMACEUTICALS COM Put 30,000 -50.00 628 -50.51 n/a n/a n/a
2023-05-15 2023-03-31 13F SYNDAX PHARMACEUTICALS COM Put 60,000 1,267 n/a n/a n/a
2021-02-16 2020-12-31 13F SYNDAX PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2020-11-16 2020-09-30 13F SYNDAX PHARMACEUTICALS COM Put 20,200 -49.50 298 -49.75 n/a n/a n/a
2020-08-14 2020-06-30 13F SYNDAX PHARMACEUTICALS COM Put 40,000 593 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.