The Securities and Exchange Commission under a second Donald Trump presidency would roll back the aggressive stance the government agency has taken against corporate giants with current chairman Gary Gensler at the helm, according to people familiar with the matter.

If Trump were to defeat President Joe Biden in November, the SEC under his administration would likely start by curtailing many of the rules recently put in place tied to the environment, according to experts and people close to the former president. An initial target of the SEC under a second Trump administration would be to roll back the new climate disclosure rules, these people explained.

Gensler and the SEC adopted a rule in March requiring large publicly traded companies to disclose their levels of greenhouse gas emissions. The largest companies are required to make climate disclosures as early as fiscal 2025, with specifics on greenhouse gas emissions as soon as fiscal 2026.

Gensler argues greenhouse gas emission levels and other climate related data have a material impact on businesses, and investors deserve to know this information.

But an SEC chaired by a Trump appointed Republican would likely remove these Biden-era disclosure requirements, these people said.

The rule “costs companies and investors a tremendous amount of money, and provides them no benefit,” said a person advising Trump on SEC related matters. Like others in this story, they were granted anonymity in order to recount private conversations.

The prospect of a Trump pullback on the SEC’s climate disclosure rules is also tied to the former president’s dislike of environmental, social and governance investment standards, some of these people explained.

During his term in office, Trump issued an executive order that made it harder for employers to offer ESG funds in employees’ 401(k) retirement plans. The Biden administration later softened the Trump rule.

In February, he said in a Truth Social post that if he is elected to a second term, he would reinstate his previous rule.

A spokesman for Trump did not return a request for comment from CNBC.

A Trump second term focused on ESG related issues at the SEC and beyond could be trouble for some of the country’s biggest investment management firms, like BlackRock and Vanguard.

The firms have long offered environmentally friendly investment options to their clients. But in recent years, just the existence of these options has created political firestorms for the firms. The backlash has been orchestrated by some of Trump‘s political allies.

A Texas public school fund recently pulled $8.5 billion out of management by BlackRock due to what it said was the firm’s reluctance to invest in fossil fuels. Florida pulled out an additional $2 billion in 2022, accusing BlackRock of putting ESG over investors. Both states are led by politically ambitious Republican governors, Ron DeSantis in Florida and Greg Abbott in Texas.

Press representatives for BlackRock and Vanguard did not immediately respond to a request for comment. But the firms have vehemently denied they are prioritizing the climate over their clients. Both BlackRock and Vanguard are fiduciaries, meaning they are legally obligated to put the interests of their clients first.

Nonetheless, a Trump ally told CNBC that he planned to speak with the former president soon about how to use the power of a Trump White House to fight back against ESG investment guidelines.

If Trump is elected to a second term and signs an order barring ESG considerations from retirement investment funds, for example, he could then call on his allies in Republican-led states to pressure investment firms to curtail their environmentally friendly investment guidance, said the person close to Trump.

“You do the executive action at the federal level, and then you call treasurers to put pressure on the investment funds to move on from ESG and have more states to divest from these funds,” said the Trump confidant.