Principal Financial Group Inc. came in 159th in Newsweek’s second annual Green Rankings of the 500 largest publicly traded companies.

The scores are based on a combination of ratings for three areas: an environmental impact score, a green policies and performance score and a reputation score. The first two categories are weighted at 45 percent each, and the third category is weighted at 10 percent.

Principal’s overall score was 74.96 out of 100, good for No. 18 in the banks and insurance industry sector. Principal scored a 73.17 in environmental impact, 47.86 in green policies and performance and 44.46 in reputation.

Principal attributes its score to having earned certification from the Forest Stewardship Council, Sustainable Forestry Initiative and the Programme for the Endorsement of Forest Certification.

The company has also been using the Environmental Protection Agency Energy Star program since 2007 to track greenhouse emissions on a monthly basis.