For the third year in a row, Elon Musk’s charitable foundation did not give away enough of its money.

And it did not miss the mark by a small amount.

New tax filings show that the Musk Foundation fell $421 million short of the amount it was required to give away in 2023. Now, Mr. Musk has until the end of the year to distribute that money, or he will be required to pay a sizable penalty to the Internal Revenue Service.

Mr. Musk, in his new role as a leader of what President-elect Donald J. Trump is calling the Department of Government Efficiency, is promising to downsize and rearrange the entire federal government — including the I.R.S. But the tax records show he has struggled to meet a basic I.R.S. rule that is required of all charity leaders, no matter how small or big their foundations.

Mr. Musk's is one of the biggest. His foundation has more than $9 billion in assets, including millions of shares in Tesla, his electric vehicle company. By law, all private foundations must give away 5 percent of those assets every year. The aim is to ensure that wealthy donors like Mr. Musk use these organizations to help the public instead of simply benefiting from the tax deductions they are afforded.

Mr. Musk’s group has fallen further and further behind. In 2021, his foundation was $41 million short, then $234 million the following year. Now, the hole is deeper still.

Private foundations do have a way to solve the problem if they do not give away enough money. They can distribute more the following year as a make-good. Mr. Musk could choose to do so in 2024.