T-Mobile US, Inc.

The full register, from 13F filings

The Register tab above is hand research: a dozen holders, each traced to the filing it came from. This asks the same question of the whole market for the quarter ended 31-mar-2026, where 1,698 managers reported a position. Broad where the research is deep, and shallow in the ways a 13F always is.

Built from 13F filings, which report US listed, long, US custodied positions only. A register from this source is a floor rather than a level: a holder's true position can be far larger, as BlackRock's ASML stake shows at 1.28m shares in a 13F against 26.3m in its 13G/A. Holdings held through derivatives, outside US custody, or below a manager's reporting obligation do not appear. Where a holder is marked as a family, its total sums several separate filing entities and describes something no single filing describes; the constituent entities and their share counts are listed so the total can be checked. That roll-up can legitimately exceed the family's own Schedule 13G, because a 13G is filed by one legal entity: Vanguard reports Alphabet through ten advisory entities, and The Vanguard Group Inc itself reported zero after its January 2026 disaggregation.

What a reader needs to know to read these numbers

• THE STORY: Deutsche Telekom AG is T-Mobile's controlling stockholder. Via its wholly owned subsidiary Deutsche Telekom Holding B.V., DT holds 582,065,875 shares of common stock (sole voting and dispositive power), last confirmed in Schedule 13D/A Amendment No. 35 (jointly filed by T-Mobile and DT, 2026-03-23) and restated as approximately 54.3% of outstanding common stock as of 17 Jul 2026 in the Q2 2026 10-Q. DT does NOT file a 13F (it is a foreign corporate parent, not a US institutional investment manager), so this position is entirely absent from data/registers/TMUS.json and had to be sourced from T-Mobile's own SEC filings (13D/A, 10-Q, 10-K, DEF 14A) rather than any 13F.
• Voting control exceeds beneficial ownership. Beyond its own 582,065,875 shares, DT holds a voting proxy and call options over 10,000,000 shares held by Signal Bright LLC, a wholly owned SoftBank Group Corp. subsidiary (per the Second Amended and Restated Stockholders' Agreement dated 22 Jun 2020 and the Proxy, Lock-Up and ROFR Agreement dated 1 Apr 2020, both between DT and SoftBank). The 13D/A's combined beneficial-ownership figure for the two entities together is 592,065,875 shares (53.7% as of 6 Feb 2026 shares outstanding, or 54.5% as of 31 Mar 2026 per the proxy). Separately, both the FY2025 10-K and the Q2 2026 10-Q state a larger 'voting control' percentage under the Proxy, Lock-Up and ROFR Agreement: approximately 56.9% as of 6 Feb 2026 and approximately 55.2% as of 17 Jul 2026, i.e. noticeably higher than DT's own beneficial stake plus Signal Bright's 10,000,000 shares alone would imply (52.8%+0.9%=53.7% at the Feb date vs the stated 56.9%). This research could not fully reconcile that gap within budget: it may reflect a broader or formula-based voting grant under the 2020 Proxy Agreement that is not a straight 1:1 mapping to Signal Bright's current share count. Both filed percentages are quoted verbatim in the register rows' method_notes rather than forced to reconcile; treat 'voting control' and 'beneficial ownership' as two distinct, both filed, both real numbers for DT.
• SoftBank still holds a T-Mobile position: 10,000,000 shares via Signal Bright LLC, entirely subject to DT's voting proxy and call options. This matches the Q1 2026 13F snapshot in data/registers/TMUS.json (SoftBank Group Corp, 10,000,000 shares) exactly, so the position appears unchanged from at least Q1 2026 through the 13D/A's 23 Mar 2026 date. SoftBank's own Q2 2026 13F-HR was not individually pulled to confirm no change since then (see unknowns); SoftBank was not in this project's pre-verified CIK list.
• DT and SoftBank/Signal Bright figures are on the SAME basis as shares_outstanding: both are plain common stock (CUSIP 872590104), the identical instrument and share class used for the company's own cover-page share count and for every institutional 13F row below. No derivative or different-class component was found for either.
• Register reconciliation, Deutsche Telekom's changing percentage. DT's own share count (582,065,875) has not visibly changed across three successive filings spanning 6 Feb 2026 (52.8%), 31 Mar 2026/23 Mar 2026 13D-A (54.5% combined / 582,065,875 DT alone), and 17 Jul 2026 (54.3%); the percentage moves only because total shares outstanding fell (buybacks) from 1,101,862,739 (6 Feb 2026) to 1,072,671,613 (17 Jul 2026), consistent with T-Mobile's active 2026 Stockholder Return Program (T-Mobile repurchased 5,106,691 shares for $984 million between 1 Jan and 6 Feb 2026 alone, per the FY2025 10-K).
• The Vanguard rule (case B, 13F-NT). Vanguard Group Inc (parent CIK 0000102909) filed Form 13F-NT, not 13F-HR, for the quarter ended 30 Jun 2026, so its TMUS position is represented here as the sum of its two successor 13F-HR filers, Vanguard Capital Management LLC and Vanguard Portfolio Management LLC (39,725,636 shares combined). See the Vanguard row's method_note for the individual entity breakdown and CIKs.
• Fiber joint ventures ARE genuine minority equity stakes, not controlled subsidiaries. Lumos (with EQT) and Metronet (with KKR) are both accounted for under the equity method per the FY2025 10-K and Q2 2026 10-Q ('Investments in entities that we do not control but have significant influence are accounted for under the equity method'), confirming T-Mobile does NOT consolidate either venture despite owning 50% of each; both are included in holdings. Two further fiber JVs (i3 Broadband with Wren House, and the GoNetspeed/Greenlight Networks combination with Oak Hill Capital) were announced via definitive agreements in Apr 2026 but had NOT closed as of the Q2 2026 10-Q (filed 23 Jul 2026); these are included as modelled/estimated rows using management's own stated expected investment amounts, clearly flagged as not-yet-closed. A fifth, much earlier-stage initiative, a satellite/spectrum-pooling joint venture with AT&T and Verizon 'agreed in principle' on 14 May 2026, has no definitive agreements, no stated equity percentage, and no stated dollar investment, so it is NOT included as a holdings row; see unknowns.
• No single combined equity-method balance-sheet line item for Lumos/Metronet together was found in either the FY2025 10-K or the Q2 2026 10-Q (searched 'equity method investment', 'carrying value', 'carrying amount', 'Investments in joint ventures'); the closest figure found is a cash-flow-statement line, 'Investments in unconsolidated affiliates, net,' which nets multiple items across periods and is not usable as a per-investee balance, so per the brief's rule against assigning a combined balance to one investee, no such figure is reported here.
• Market capitalisation ($192.79bn) and share price ($179.73) are stockanalysis.com's real-time figures as of 17 Aug 2026, 12:15pm ET (the day of this research), used only because they were the most current available; they are basis 'aggregator'/confidence 'reported', not filed figures.
• Self-gate check: summing every non-aggregate register row's shares (Deutsche Telekom 582,065,875 + SoftBank/Signal Bright 10,000,000 + all 12 institutional 13F rows, i.e. everything except the 'group of 20' aggregate insider row, which is excluded as an aggregate/overlap row) gives 760,737,623 shares against 1,072,671,613 shares outstanding, or 70.9%. Excluding Deutsche Telekom and SoftBank entirely, the 12 ordinary institutional holders alone sum to 168,671,748 shares, or 15.7% of the company, which sits at the low end of this project's usual 15-45% institutional band. The 70.9% total is far above that band, and Deutsche Telekom's 54.3% controlling stake fully explains the excess: 70.9% minus DT's 54.3% minus SoftBank's 0.9% lands almost exactly on the 15.7% institutional-only figure. This is the expected shape for a controlled company and is not a data error.