(Bloomberg) — AT&T Inc., the biggest U.S. phone company, said its fourth-quarter results will include a non-cash gain of about $7.6 billion to account for changes in its pension fund and retiree benefit plans.

The increase is due to an adjustment in the carrier’s assumptions on interest rates and a better-than-expected return on assets, Dallas-based AT&T said yesterday in a filing. Updated estimates for mortality and other demographic changes offset some of the gains, the company said.

AT&T is scheduled to report its quarterly earnings on Jan. 28. Leaving out one-time items such as the pension benefit, profit will be 51 cents a share, up from 44 cents a year earlier, on sales of $33.1 billion, according to the average of analysts’ estimates compiled by Bloomberg.

The company said yesterday it’s also taking a $500 million charge in the quarter for a voluntary retirement package accepted by 4,200 employees. It didn’t provide further information about its results for the period.

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