Anthem, a subsidiary of Blue Cross Blue Shield, is the latest health insurer to raise its revenue projections for 2018 thanks to the Republican-led tax bill signed into law by President Trump.

The company recorded a one-time benefit of $1.1 billion from $368.4 million in 2016 because of the tax law, which lowers the corporate tax rate. The results beat analysts' estimates, reporting revenues of $22.4 billion in the fourth quarter, up 4.5 percent from a year ago and more than the $22.2 billion analysts expected.

Its 2018 forecast included a net benefit of about $2 a share and it expects adjusted earnings to be more than $15 a share.

Anthem did better than it expected in its Obamacare products, which are sold through exchanges and subsidized by the government for people who have to buy their own medical coverage because they don't get it through their jobs or through a government program.

Executives credited the result to the suspension of the health insurance tax, which goes back into effect this year but will be suspended again the following year, as well as lower claims filed by beneficiaries.

"As a result, our business was slightly profitable during the year, better than the relatively break-even performance we had expected," said John Gallina, the company's chief financial officer.

Anthem President and CEO Gail Boudreaux, who took the helm at Anthem two months ago replacing Joseph Swedish, projected enrollment in Obamacare plans would fall in 2018 because the company had exchanges in different states. Overall, she predicted that these plans, sold on and off the exchanges, would have 950,000 fewer people enrolled. The company has said it would consider re-entering some markets in 2019 if the circumstances change.

Anthem also does business with Medicare and Medicaid, where it hopes to expand, as well as with employers. The number of people enrolled in its plans overall totaled about 40.2 million at the end of the fourth quarter, an increase of 325,000 members.

Shares in Anthem and other health insurers and pharmacy benefits managers fell Tuesday after Amazon.com Inc., JPMorgan Chase & Co., and Berkshire Hathaway Inc. said they plan to form a new company to address healthcare for their workers. Anthem shares dropped 5.3 percent.