In 1999, Deutsche Telekom formed the holding company T-Mobile International AG for its mobile communications subsidiaries.

By combining its previously separated fixed and mobile subsidiaries to form integrated local businesses, T-Mobile International itself was merged into Deutsche Telekom AG.

[2] When T-Mobile International AG existed, the holding company was based in Bonn, Germany, and its subsidiaries operated GSM-, UMTS- and LTE-based cellular networks in Europe, the United States, Puerto Rico and the U.S. Virgin Islands.

It was the world's thirteenth-largest mobile-phone service provider by subscribers, and the fourth-largest multinational after the UK's Vodafone, India's Airtel, and Spain's Telefónica.

[3] Germany's first mobile-communications services were radiotelephone systems that were owned and operated by the state postal monopoly, Deutsche Bundespost.

[6] This process of deregulation continued in November 1996, when DT was privatized and had the largest European IPO at the time, with the stock abbreviation 'DT 1'.

[citation needed] On 5 July 2005 Deutsche Telekom transformed its structure and adopted a regional setup (Germany, Europe, US).

In April 2001, it acquired one hundred percent and subsequently introduced the T-Mobile brand in Austria by rebranding max.mobil.

It later rebranded again to Magenta Telekom on 6 May 2019, after acquiring the Austrian operations of UPC from Liberty Global in December 2017.

T-Mobile entered the Croatian market in October 1999 when DT initially acquired a thirty-five percent interest in Hrvatski telekom, including its cell phone service provider Cronet.

Two years later, DT signed an agreement with the Croatian government to acquire the additional 16 percent needed for a majority holding.

On 19 October 2005, T-Mobile was the first operator in the Czech Republic to launch this third-generation technology under the name Internet 4G.

[13] Germany's initial mobile communications services were radiotelephone systems that were owned and operated by the state postal monopoly, Deutsche Bundespost.

On 1 July 1992, Deutsche Bundespost Telekom's DeTeMobil subsidiary began operating Germany's first GSM 900 MHz frequency cellular network, which the organization referred to as D-Netz.

The T-Mobile brand entered the Montenegrin market in 2006 through the acquisition of MoNet GSM mobile provider.

Although the acquisition by Magyar Telekom was done in 2005, it was not until 26 September 2006, that the MoNet GSM operator was re-branded as T-Mobile Montenegro.

[16][17] T-Mobile Polska serves over thirteen million customers,[18] and owns licenses for 900, 1800MHz bands which are used for GSM, 800, 900, 1800, 2100 2600MHz for LTE and 2100 (DSS), 3500MHz for 5G NR NSA.

Mobile data services are provided on 4G, 3G, GSM network with EDGE extension and on UMTS with DC-HSPA+ 42 Mbit/s[21] and HSUPA 5,8 Mbit/s.

[26] In March 2010, the European Commission approved this merger on the condition that the combined company sell 25% of the spectrum it owns on the 1800 MHz radio band and amend a network sharing agreement with smaller rival 3.

The company operates the second largest wireless network in the U.S.[30][31] market with over 95 million customers[32] and annual revenues of $32 billion.

[40] It provides coverage in areas where it does not own radio frequency spectrum licenses via roaming agreements with other operators of compatible networks.

The T-Mobile HotSpot service offers access to a nationwide network of approximately 8,350 access points, installed in venues such as Starbucks coffeehouses, FedEx Office Office and Print Centers, Hyatt hotels and resorts, Red Roof Inns, Sofitel hotels, Novotel hotels, the airline clubs of American Airlines, Delta Air Lines, United Airlines and US Airways, and airports.

[citation needed] After a failed attempt by AT&T in 2011 to purchase the company in a $39 billion stock and cash offer (which was withdrawn after being faced with significant regulatory and legal hurdles, along with heavy resistance from the U.S. government and the Sprint Corporation),[45] T-Mobile USA announced its intent to merge with MetroPCS Communications, Inc., the sixth largest carrier in the U.S., to improve its competitiveness with other national carriers; the deal was approved by the Department of Justice and Federal Communications Commission in March 2013.

[46][47][48] The merger agreement gave Deutsche Telekom the option to sell its 72% stake in the merged company, valued at around $14.2 billion, to a third-party before the end of the 18-month lock-up period.

[52] The merger was completed on 1 April 2020 with Deutsche Telekom holding owning 43% of the company, SoftBank at 24% and the remaining 33% to the public shareholders.

[55] The five-note T-Mobile audio logo was composed by Lance Massey[56] in 1999, and was originally part of the song ("Hello Hola" by Clan Chi) used to promote DT's Tour de France bicycle team.

[57] Deutsche Telekom, has served as the kit sponsor for German Bundesliga club Bayern Munich since 2002.

T-Mobile also has banner ads at some matches of Mexico's top association football league, Liga MX, despite not having a presence in that country.