Former President Donald J. Trump told a group of America’s most powerful chief executives on Thursday that he intended to cut the corporate tax rate to 20 percent from 21 percent, according to three people who attended the meeting and who spoke on the condition of anonymity because the ground rules stipulated the meeting was off the record.

Mr. Trump made the remarks from a comfortable gray armchair during a conversation with his former economic adviser Larry Kudlow in front of the audience of dozens of leading chief executives, including Tim Cook of Apple, Jamie Dimon of JPMorgan Chase, Doug McMillon of Walmart and Charles W. Scharf of Wells Fargo.

They had gathered on Thursday morning in Washington for a meeting of the Business Roundtable, an influential corporate group, and there was said to be palpable relief in the room when Mr. Trump, who has been trying to woo business leaders as potential donors, told the executives much of what they had hoped to hear.

Many leaders in corporate America have been nervous that in a second term, Mr. Trump might not be as friendly toward them as he was in his first. Many ended up abandoning him and publicly criticizing him, especially after the attack on the Capitol on Jan. 6, 2021.

Mr. Trump, whose public speeches are often characterized by conspiratorial promises to root “Communists” out of government and hard-line policies such as overseeing the largest deportation operation in American history, was described by one of the people who attended the meeting to have sounded relatively more measured than usual, modulating his messages for the elite audience. He most strikingly softened his language about immigration.

But it was his spiel about taxes that seemed most visibly pleasing to the executives in the room, according to people who attended the meeting.