Syndax Pharmaceuticals, Inc.
US ˙ NasdaqGS ˙ US87164F1057

SecuritySNDX / Syndax Pharmaceuticals, Inc.
InstitutionOptiver Holding B.V.
Latest Disclosed Ownership343 shares
Latest Disclosed Value $ 8,012
Optiver Holding B.V. reports 104.17% increase in ownership of SNDX / Syndax Pharmaceuticals, Inc.

On June 2, 2026 - Optiver Holding B.V. filed a 13F-HR/A form disclosing ownership of 343 shares of Syndax Pharmaceuticals, Inc. (US:SNDX) valued at $8,012 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 168 shares of Syndax Pharmaceuticals, Inc.. This represents a change in shares of 104.17% during the quarter. The current value of the position is $6,291 USD.

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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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)
2026-06-02 2026-03-31 13F/A-1 SYNDAX PHARMACEUTICALS COM 87164F105 343 175 104.17 8 166.67 0.0000
2026-05-15 2026-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 343 175 8 0.0000
2026-02-17 2025-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 168 -551 -76.63 4 -72.73 0.0000
2025-11-10 2025-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 719 208 40.70 11 175.00 0.0000
2025-08-14 2025-06-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 511 240 88.56 5 33.33 0.0000
2025-05-15 2025-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 271 271 3 0.0000
2022-05-16 2022-03-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 0 -5,147 -100.00 0 -100.00
2022-02-14 2021-12-31 13F SYNDAX PHARMACEUTICALS COM 87164F105 5,147 0 0.00 98 0.00 0.0001
2021-11-15 2021-09-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 5,147 -3,993 -43.69 98 -37.58 0.0001
2021-08-16 2021-06-30 13F SYNDAX PHARMACEUTICALS COM 87164F105 9,140 9,140 157 0.0002
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.