The deal, first revealed last year, will see Czech private equity firm PPF Group acquiring the majority stake held by AT&T, which had picked up the holding after it bought Time Warner in 2018.
The conclusion of the deal also means AT&T is no longer liable for a $575m backstop to CME debt.
AT&T, which has been making a swathe of changes and layoffs to the operations of WarnerMedia this year, said the sale “is consistent with our ongoing efforts to monetise non-core assets to drive incremental shareholder value.”
The company said it is looking to reduce its debt further “and will remain opportunistic around opportunities to further improve its borrowing costs.”
PPF is the private equity firm operated by investor Petr Kellner, who has previously worked with Czech financier Daniel Kretinsky. The latter has been linked with a potential move for German broadcast giant ProSiebenSat.1, in which he holds a 10% stake.