Actually, he did not.

“I have paid federal income tax every year since 1944,” Mr. Buffett wrote in a letter released Monday.

“My 2015 return shows adjusted gross income of $11,563,931,” he revealed. “My deductions totaled $5,477,694.” About two-thirds of those represented charitable contributions, he said. Most of the rest were related to Mr. Buffett’s state income tax payments.

Mr. Buffett, the chairman of Berkshire Hathaway and one of the richest men in the world, went on to say: “My federal income tax for the year was $1,845,557. Returns for previous years are of a similar nature in respect to contributions, deductions and tax rates.”

Last year, Mr. Buffett paid about 16 percent of his reported income in federal income taxes.

“I have copies of all 72 of my returns,” Mr. Buffett added, “and none uses a carry forward,” the provision that allows taxpayers like Mr. Trump to use losses from one year to avoid paying personal federal income taxes both on some previous tax returns and in future years.

Mr. Trump had previously claimed, without producing any evidence, that Mr. Buffett declared $873 million in losses.

As it turns out, the charitable contributions that Mr. Buffett did deduct from his income make up just a tiny portion of the more than $2.85 billion he donated to charity last year, he said. The reason is that the tax code limits the amount that an individual can claim in charitable deductions. Mr. Buffett, 86, has pledged to give most of his $65 billion fortune away.