Aflac Inc. has revised its estimate on the impact of U.S. tax reform on net earnings and total shareholders' equity for the fourth quarter of 2017 to include an additional tax benefit of $233 million.

The company had previously released a preliminary estimate of $1.7 billion. This adjustment will also impact any U.S. GAAP or non-GAAP financial measures that use net earnings or total shareholders' equity.

Aflac said it may revise future estimates as it is relying upon guidance provided by the SEC that provides a measurement period of up to one year from the enactment date of Dec. 22, 2017, to complete the accounting for the effects of tax reform.