T-Mobile US, Inc.
MX ˙ BMV ˙ US8725901040
SecurityMX:TMUS / T-Mobile US, Inc.
InstitutionBanco Santander, S.A.
Latest Disclosed Ownership104,540 shares
Latest Disclosed Value $ 21,956,536
Banco Santander, S.A. reports 100.43% increase in ownership of TMUS / T-Mobile US, Inc.

On May 8, 2026 - Banco Santander, S.A. filed a 13F-HR form disclosing ownership of 104,540 shares of T-Mobile US, Inc. (MX:TMUS) valued at $21,956,536 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 52,159 shares of T-Mobile US, Inc.. This represents a change in shares of 100.43% during the quarter.

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)
2026-05-08 2026-03-31 13F T-MOBILE US COM 872590104 104,540 52,381 100.43 21,957 107.33 0.1037
2026-02-13 2025-12-31 13F T-MOBILE US COM 872590104 52,159 -34,680 -39.94 10,590 -49.05 0.0793
2025-11-12 2025-09-30 13F T-MOBILE US COM 872590104 86,839 4,087 4.94 20,788 5.43 0.1846
2025-08-01 2025-06-30 13F T-MOBILE US COM 872590104 82,752 -32,134 -27.97 19,716 -35.65 0.1872
2025-05-09 2025-03-31 13F T-MOBILE US COM 872590104 114,886 4,980 4.53 30,641 26.31 0.3381
2025-02-07 2024-12-31 13F T-MOBILE US COM 872590104 109,906 -202 -0.18 24,260 6.77 0.2919
2024-11-12 2024-09-30 13F T-MOBILE US COM 872590104 110,108 498 0.45 22,722 17.66 0.2678
2024-07-29 2024-06-30 13F T-MOBILE US COM 872590104 109,610 -466 -0.42 19,311 7.49 0.2393
2024-05-10 2024-03-31 13F T-MOBILE US COM 872590104 110,076 -21,091 -16.08 17,967 -14.57 0.2166
2024-02-09 2023-12-31 13F T-MOBILE US COM 872590104 131,167 -661 -0.50 21,030 13.91 0.2485
2023-11-08 2023-09-30 13F T-MOBILE US COM 872590104 131,828 3,316 2.58 18,463 3.43 0.2617
2023-08-14 2023-06-30 13F T-MOBILE US COM 872590104 128,512 -1,133 -0.87 17,850 -4.94 0.2341
2023-05-10 2023-03-31 13F T-MOBILE US COM 872590104 129,645 2,200 1.73 18,778 5.24 0.2810
2023-02-13 2022-12-31 13F T-MOBILE US COM 872590104 127,445 -1,294 -1.01 17,842 3.29 0.2680
2022-11-08 2022-09-30 13F T-MOBILE US COM 872590104 128,739 -1,428 -1.10 17,273 -1.37 0.2304
2022-07-28 2022-06-30 13F T-MOBILE US COM 872590104 130,167 -50,295 -27.87 17,513 -24.39 0.2334
2022-05-09 2022-03-31 13F T-MOBILE US COM 872590104 180,462 62,591 53.10 23,162 69.44 0.2486
2022-02-09 2021-12-31 13F T-MOBILE US COM 872590104 117,871 24,540 26.29 13,670 14.64 0.0737
2021-11-08 2021-09-30 13F T-MOBILE US COM 872590104 93,331 12,094 14.89 11,924 1.35 0.0641
2021-07-29 2021-06-30 13F T-MOBILE US COM 872590104 81,237 76,416 1,585.07 11,765 1,847.85 0.0657
2021-05-10 2021-03-31 13F T-MOBILE US COM 872590104 4,821 -128 -2.59 604 -9.58 0.0043
2021-02-12 2020-12-31 13F T-MOBILE US COM 872590104 4,949 -473 -8.72 668 7.74 0.0048
2020-11-09 2020-09-30 13F T-MOBILE US COM 872590104 5,422 -1,381 -20.30 620 -12.43 0.0082
2020-08-05 2020-06-30 13F T-MOBILE US COM 872590104 6,803 6,803 708 0.0092
2020-05-11 2020-03-31 13F T MOBILE US COM 872590104 0 -38,931 -100.00 0 -100.00
2020-02-07 2019-12-31 13F T MOBILE US COM 872590104 38,931 38,931 3,053 0.0282
2019-11-06 2019-09-30 13F T MOBILE US COM 872590104 0 -5,341 -100.00 0 -100.00
2019-08-07 2019-06-30 13F T MOBILE US COM 872590104 5,341 5,341 396 0.0040
2019-02-12 2018-12-31 13F T MOBILE US COM 872590104 0 -9,209 -100.00 0 -100.00
2018-11-13 2018-09-30 13F T MOBILE US COM 872590104 9,209 9,209 646 0.0074
2018-02-14 2017-12-31 13F T MOBILE US COM 872590104 0 -166,000 -100.00 0 -100.00
2017-11-13 2017-09-30 13F T MOBILE US COM 872590104 166,000 166,000 6,502 0.1072
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.