Y-mAbs Therapeutics, Inc.
US ˙ NasdaqGS ˙ US9842411095
ACEST SIMBOL NU MAI ESTE ACTIV

SecurityYMAB / Y-mAbs Therapeutics, Inc.
InstitutionQUANTITATIVE MASTER SERIES LLC - Master Small Cap Index Series
Latest Disclosed Ownership63,465 shares
Latest Disclosed Value $ 286,227
QUANTITATIVE MASTER SERIES LLC - Master Small Cap Index Series ownership in YMAB / Y-mAbs Therapeutics, Inc.

On August 26, 2025 - QUANTITATIVE MASTER SERIES LLC - Master Small Cap Index Series filed a NPORT-P form disclosing ownership of 63,465 shares of Y-mAbs Therapeutics, Inc. (US:YMAB) valued at $286,227 USD as of June 30, 2025. The entity filed a previous NPORT-P on May 28, 2025 disclosing 63,465 shares of Y-mAbs Therapeutics, Inc.. This represents a change in shares of 0.00% during the quarter. The current value of the position is $546,434 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)
2025-08-26 2025-06-30 NP Y-mAbs Therapeutics EC US9842411095 63,465 0 0.00 286 1.78 0.0064
2025-05-28 2025-03-31 NP Y-mAbs Therapeutics EC US9842411095 63,465 0 0.00 281 -43.35 0.0067
2025-02-25 2024-12-31 NP Y-mAbs Therapeutics EC US9842411095 63,465 -9,869 -13.46 497 -48.55 0.0109
2024-11-26 2024-09-30 NP Y-mAbs Therapeutics EC US9842411095 73,334 4,756 6.94 964 16.43 0.0182
2024-08-26 2024-06-30 NP Y-mAbs Therapeutics EC US9842411095 68,578 4,613 7.21 828 -20.38 0.0169
2024-05-28 2024-03-31 NP Y-mAbs Therapeutics EC US9842411095 63,965 0 0.00 1,040 138.53 0.0217
2024-02-26 2023-12-31 NP Y-mAbs Therapeutics EC US9842411095 63,965 0 0.00 436 25.29 0.0093
2023-11-28 2023-09-30 NP Y-mAbs Therapeutics EC US9842411095 63,965 0 0.00 349 -19.82 0.0091
2023-08-25 2023-06-30 NP Y-mAbs Therapeutics EC US9842411095 63,965 6,794 11.88 434 51.75 0.0103
2023-05-26 2023-03-31 NP Y-mAbs Therapeutics EC US9842411095 57,171 0 0.00 286 2.88 0.0076
2023-02-24 2022-12-31 NP Y-mAbs Therapeutics EC US9842411095 57,171 0 0.00 279 -66.26 0.0077
2022-11-25 2022-09-30 NP Y-mAbs Therapeutics EC US9842411095 57,171 3,722 6.96 824 1.98 0.0236
2022-08-25 2022-06-30 NP Y-mAbs Therapeutics EC US9842411095 53,449 0 0.00 809 27.44 0.0223
2022-05-26 2022-03-31 NP Y-mAbs Therapeutics EC US9842411095 53,449 0 0.00 635 -26.79 0.0148
2022-02-25 2021-12-31 NP Y-mAbs Therapeutics EC US9842411095 53,449 0 0.00 866 -43.21 0.0188
2021-11-24 2021-09-30 NP Y-mAbs Therapeutics EC US9842411095 53,449 0 0.00 1,525 -15.56 0.0336
2021-08-26 2021-06-30 NP Y-mAbs Therapeutics EC US9842411095 53,449 6,689 14.30 1,807 27.72 0.0388
2021-05-27 2021-03-31 NP Y-mAbs Therapeutics EC US9842411095 46,760 -1,557 -3.22 1,414 -40.89 0.0321
2021-02-25 2020-12-31 NP Y-mAbs Therapeutics EC US9842411095 48,317 0 0.00 2,392 29.02 0.0613
2020-11-25 2020-09-30 NP Y-mAbs Therapeutics EC US9842411095 48,317 -2,371 -4.68 1,855 -15.30 0.0595
2020-08-27 2020-06-30 NP Y-mAbs Therapeutics EC US9842411095 50,688 12,004 31.03 2,190 116.95 0.0716
2020-06-01 2020-03-31 NP Y-mAbs Therapeutics EC US9842411095 38,684 0 0.00 1,010 -16.47 0.0413
2020-02-27 2019-12-31 NP Y-mAbs Therapeutics EC 984241109 38,684 7,778 25.17 1,209 50.06 0.0364
2019-11-27 2019-09-30 NP Y-mAbs Therapeutics EC US9842411095 30,906 30,906 805 0.0266
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.