The deal was approved last month by US telecommunications and anti-trust regulators.
The new company, which will take the name AT&T Inc, will have combined annual revenue of roughly $90bn, making it the largest telecom company in the US.
AT&T was the country’s leading long-distance Bell company, prized for its corporate services business, while SBC was the second largest local phone outfit after Verizon Communications Inc.
Separately, regulators in California also approved on Friday Verizon’s acquisition of MCI Inc, which is AT&T’s closest rival. The Verizon-MCI deal is now expected to close either next month or early January, according to Verizon.
