Trump's push for renewed scrutiny could give some plans pause when it comes to including these funds.
"The landscape is still in flux," said David Levine, principal at Groom Law Group. "It will be interesting to see where adoption goes, especially as the DOL gives it more thought."
Ultimately, the Department of Labor's analysis could lead to stronger statements on ESG or more tweaking to the policies on these kinds of investments in retirement plans, Levine said.
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Companies that have shied away from offering ESG investments in retirement plans have done so largely for two reasons: regulatory concerns and the fear that they could be perceived as imposing moral beliefs on their workers, according to experts.
Fugere, an advocate for ESG investments, argues that keeping investors' best interests in mind — what it means to be a fiduciary — is synonymous with making ESG investments available.
"Failure to take climate change into account really in the end is failure of fiduciary duty," Fugere said.
While Trump's executive order broadly favors traditional energy companies, Fugere said, that cannot stop the transformation to clean energy that is already underway.
"This is a last-ditch effort to retain the dominance of the oil and gas industry," Fugere said. "But, in the end, it can't be successful."
"The world is changing," she said.