AT&T filed for approval for the proposal with the U.S. Department of Labor on Thursday. It said the move would not significantly affect company earnings.

AT&T's pension plan was underfunded by about $10.2 billion at the end of 2011, a company spokeswoman said.

"We're making this contribution, which is many times above our estimated required funding for 2013, at a time when many companies have eliminated their pensions," the spokeswoman said.

The proposal comes after rival Verizon Communications Inc said on Wednesday that it will transfer $7.5 billion in pension obligations to insurer Prudential, removing a quarter of its long-term employee retirement burden with a single upfront payment.

The move follows a similar deal that General Motors Co did with Prudential earlier this year.

(Reporting by Nicola Leske; Editing by Leslie Gevirtz)

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