T-Mobile US, Inc.
MX ˙ BMV ˙ US8725901040
SecurityMX:TMUS / T-Mobile US, Inc.
InstitutionHarbor Advisors LLC
Latest Disclosed Ownership20,650 shares
Latest Disclosed Value $ 4,337,120
Harbor Advisors LLC ownership in TMUS / T-Mobile US, Inc.

On May 7, 2026 - Harbor Advisors LLC filed a 13F-HR form disclosing ownership of 20,650 shares of T-Mobile US, Inc. (MX:TMUS) valued at $4,337,120 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 30, 2026 disclosing 20,650 shares of T-Mobile US, Inc.. This represents a change in shares of 0.00% 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)
2026-05-07 2026-03-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 4,337 3.46 0.6266
2026-01-30 2025-12-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 4,193 -15.19 0.6297
2025-11-12 2025-09-30 13F T-MOBILE US COM 872590104 20,650 0 0.00 4,943 0.47 0.7624
2025-08-13 2025-06-30 13F T-MOBILE US COM 872590104 20,650 0 0.00 4,920 -10.66 0.8052
2025-05-15 2025-03-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 5,508 20.82 0.9563
2025-02-11 2024-12-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 4,558 6.97 0.7161
2024-11-14 2024-09-30 13F T-MOBILE US COM 872590104 20,650 0 0.00 4,261 17.12 0.7132
2024-07-30 2024-06-30 13F T-MOBILE US COM 872590104 20,650 0 0.00 3,638 7.95 0.6671
2024-05-01 2024-03-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 3,370 1.81 0.6191
2024-02-01 2023-12-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 3,311 14.45 0.6330
2023-11-07 2023-09-30 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,892 0.84 0.6195
2023-08-15 2023-06-30 13F/A-1 T-MOBILE US COM 872590104 20,650 0 0.00 2,868 -4.08 0.6096
2023-08-01 2023-06-30 13F T-MOBILE US COM 872590104 20,650 2,868
2023-05-11 2023-03-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,991 3.42 0.6999
2023-02-13 2022-12-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,891 4.33 0.7217
2022-11-07 2022-09-30 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,771 -0.25 0.7456
2022-08-05 2022-06-30 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,778 4.83 0.6744
2022-05-16 2022-03-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,650 10.65 0.5433
2022-02-14 2021-12-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,395 -9.21 0.4454
2021-10-29 2021-09-30 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,638 -11.80 0.5277
2021-08-03 2021-06-30 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,991 15.62 0.5915
2021-05-04 2021-03-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,587 -7.11 0.5735
2021-02-11 2020-12-31 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,785 17.91 0.6236
2020-11-09 2020-09-30 13F T-MOBILE US COM 872590104 20,650 0 0.00 2,362 9.81 0.5551
2020-08-03 2020-06-30 13F T-MOBILE US COM 872590104 20,650 150 0.73 2,151 25.06 0.5513
2020-05-21 2020-03-31 13F T MOBILE US COM 872590104 20,500 0 0.00 1,720 6.97 0.5220
2020-02-13 2019-12-31 13F T MOBILE US COM 872590104 20,500 0 0.00 1,608 -0.43 0.4357
2019-11-13 2019-09-30 13F T MOBILE US COM 872590104 20,500 0 0.00 1,615 6.25 0.4621
2019-08-14 2019-06-30 13F T MOBILE US COM 872590104 20,500 2,500 13.89 1,520 22.19 0.4543
2019-05-15 2019-03-31 13F T MOBILE US COM 872590104 18,000 0 0.00 1,244 8.65 0.4010
2019-02-15 2018-12-31 13F T MOBILE US COM 872590104 18,000 0 0.00 1,145 -9.34 0.4453
2018-11-14 2018-09-30 13F T MOBILE US COM 872590104 18,000 0 0.00 1,263 17.38 0.3922
2018-08-07 2018-06-30 13F T MOBILE US COM 872590104 18,000 0 0.00 1,076 -2.09 0.3464
2018-05-11 2018-03-31 13F T MOBILE US COM 872590104 18,000 0 0.00 1,099 -3.85 0.3701
2018-02-07 2017-12-31 13F T MOBILE US COM 872590104 18,000 0 0.00 1,143 2.97 0.3882
2017-10-26 2017-09-30 13F T MOBILE US COM 872590104 18,000 8,068 81.23 1,110 84.39 0.4065
2017-08-14 2017-06-30 13F T MOBILE US COM 872590104 9,932 0 0.00 602 -6.23 0.2381
2017-05-15 2017-03-31 13F T MOBILE US COM 872590104 9,932 0 0.00 642 12.43 0.2733
2017-01-30 2016-12-31 13F T MOBILE US COM 872590104 9,932 9,932 571 0.2738
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.