Justice is investigating a potential plot to hinder a new technology called eSIM, short for embedded-SIM, the New York Times reported.
The probe is also looking into whether industry standards organization GSMA was part of the collusion.
Carriers like AT&T and Verizon have increasingly been losing subscribers to T-Mobile, thanks to more consumer friendly policies ranging from cheaper worldwide roaming to the elimination of hidden fees and long-term contracts.
An AT&T spokesman said in an email: "Along with other GSMA members, we have provided information to the government in response to their requests and will continue to work proactively within GSMA, including with those who might disagree with the proposed standards".
NY Times Editorial: Scott Pruitt Has Become Ridiculous
However, Trump has thrown his support behind the administrator, tweeting earlier this month that Pruitt was doing a "great job". That's not to mention Pruitt's continued efforts to dismantle the legacy of the very agency he heads.
AT&T sent us a statement, too. The probe began after a device maker, identified in the Times report as Apple, and a separate wireless carrier filed a formal complaint. Despite eSIM's obvious advantages, it has yet to achieve any significant presence in the market, with only a few notable devices having adopted it so far, such as Google's Pixel 2 and the Apple Watch 3.
"In the context of antitrust and IP, we will be inclined to investigate and enforce when we see evidence of collusive conduct undertaken for the goal of fixing prices, or excluding particular competitors or products", Delrahim said in a speech this month at a conference in Washington, D.C. He previously warned of the potential for "cartellike behavior" by competitors that got together with standards-setting organizations.
The person also said the Justice Department previously examined this matter in 2016, but ended up dropping the investigation. For companies like Apple, eSIM technology would free up storage space in devices to use for other technologies like bigger processors and batteries. AT&T and Time Warner have strongly disputed the claims in a federal trial that is expected to end this month.
Consumer advocates learned in February that Verizon was apparently planning to lock phones as an anti-theft measure, and later were told by industry participants that Verizon was working with AT&T in hopes of convincing the GSMA to create a standard for locking the phones, according to Harold Feld, a senior vice president at Public Knowledge.