A new change in the Republican tax bill would allow energy companies classified as publicly traded partnerships to take the pass-through business deduction.

An amendment originally considered by the GOP would have also allowed many large private-equity firms, like Blackstone, to take this break as well.

A provision in the final Senate Republican tax bill would serve as a huge boon to large energy companies.

An amendment introduced on Friday night by Sen. John Cornyn – the second-ranking Republican in the Senate – would have allowed owners of publicly traded partnerships (PTPs) to take a deduction for pass-through businesses on their income. That deduction was increased to 23% in the latest version of the Senate Tax Cuts and Jobs Act.

The original amendment would have allowed financial services firms classified as PTPs, such as private equity giants Blackstone and Carlyle Group, to take the pass-through benefit. When the language was added to the final version of the GOP bill, however, guardrails were put up to prevent these companies from benefitting.

“Financial PTPs primarily earn their income from the sale of securities and dividends, both of which are taxed at the capital gains rate – a rate lower than what’s required to claim the pass-through deduction for business income in the Senate bill,” an aide to Cornyn told Business Insider. “Further, the fee income you referenced is not qualifying income under 7704(d). They are not intended to benefit from this provision.”

The change in the final bill, however, does allow oil and gas firms that are PTPs to take the benefit. Many energy companies are classified as master limited partnerships (MLPs), a type of PTP, to enjoy the tax benefits of a partnership. Many large MLPs are based in Cornyn’s home state of Texas.

Republicans have touted the pass-through provision, which allows companies in which the owner takes business profits as income, as a way to boost small businesses.

Lees ook op Business Insider Winkelketens Expresso en Claudia Sträter binnen maand na doorstart weer doorverkocht

Victor Fleischer, a tax-law professor at the University of San Diego and New York Times contributor, first pointed out the Cornyn amendments on Twitter.

“One of his amendments extended the pass through rate to oil and gas PTPs; the other extended to Financial PTPs,” he told Business Insider after the final bill text was made public. “Only the oil and gas amendment made it into the final bill.”

Fleischer said that while the final TCJA did not benefit private equity firms like the Cornyn amendment did, the bill did give a “MASSIVE new benefit to oil and gas PTPs.”

The Senate passed the final version of the TCJA on Saturday by a vote of 51 to 49.