S&P 500 earnings hinge on Trump, Harris tax plans, Goldman says

Tax policies touted in the U.S. presidential election could have a big impact on S&P 500 earnings, according to Goldman Sachs Inc. strategists.

They estimate profits could shift in the ballpark range of 5% to 10%, depending on how the policies are enacted and whether Donald Trump's 2017 tax cuts are allowed to expire, the team including Ben Snider and David Kostin wrote in a note dated Sept. 4.

While Republican nominee Trump's proposals would likely boost earnings, those floated by his Democratic opponent Kamala Harris would have the opposite effect, the strategists said. But they noted that both candidates' tax pledges would face hurdles to get enacted.

Trump's promise to cut the federal corporate tax rate to 15% from 21% would raise S&P 500 earnings by about 4%, the strategists wrote. Harris' proposal to lift the rate to 28% would reduce earnings by about 5%, they said, while changes to the taxation of foreign income and an increase in the alternative minimum tax rate would cut earnings by about 8%.

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In addition, the extension or expiry of the tax cuts enacted by the Trump administration in 2017 would shift S&P 500 earnings by as much as 2%, they said.

"These sensitivities only reflect the direct impact of changing tax policy and do not take into account secondary impacts, such as through changes in economic activity," the strategists wrote. And they added a caveat: "Prediction markets show a substantial probability that the next U.S. president will not have control over Congress, and campaign proposals do not always translate into legislative reality."

Trump and running mate JD Vance are campaigning on a grab bag of tax cut proposals that could collectively cost as much as $10.5 trillion over a decade, more than the combined budgets of every domestic federal agency. Harris has also called for some tax cuts — like exempting tips from taxation and expanding the child tax credit — that would cost roughly $2 trillion and be paid for through increased taxes on corporations and wealthy individuals.

The 2017 Trump tax overhaul boosted earnings-per-share for S&P 500 companies by 12% the following year, and resulted in a rally in the index of about 10%. Still, this time round it is likely that "most investors will wait for legislative clarity before fully adjusting portfolios to reflect any changes in tax policy," the Goldman strategists wrote.