In three consecutive years, Donald Trump has received a property tax credit for people with incomes of less $500,000.

The perk from the New York State School Tax Relief Program, known as STAR, was small — only $302 off of Trump's tax bill of more than $175,000 for his penthouse apartment in Trump Tower. Normally, the benefit only is given to people who both apply and demonstrate that their incomes are below the half-million-dollar threshold.

But late Tuesday, New York City's Department of Finance said that it believes Trump received the tax benefit in error. Trump had previously qualified for the state tax break, which is administered by the city, before it was eliminated for upper income taxpayers in 2010. Due to an apparent error, Trump began receiving the benefit again in 2013. The tax break is a partial exemption from school property taxes.

State wants money back

New York would now like its money back.

"Mr. Trump should not have received this benefit after the income limit law changed, and he should immediately return its value to state taxpayers," said Amy Spitalnick, a spokeswoman for New York City.

On Tuesday afternoon, Trump campaign manager Corey Lewandowski said Trump's failure to reject the tax credit was an oversight.

"With all due respect, I don't think he would have noticed that," Lewandowski said of Trump. "He was not aware of it until today. Maybe $300 on other peoples taxes is a big deal, but not on his."

'Confirm he was entitled to this'

According to the claim form for the tax credit, taxpayers must both apply for the credit and submit a copy of their tax returns. Lewandowski said this had not occurred.

"In 2010, they changed the program to require income verification, at which point Mr. Trump no longer applied for the credit," Lewandowski said.

Crain's New York Business first reported that Trump received the tax benefit in a February 2016 tax bill that is publicly available through the website of New York City's Finance Department.

A New York City real estate tax attorney contacted by The Associated Press called the situation unusual, as taxpayers are not supposed to receive the credit without formally applying for it and submitting proof of their incomes.

"The only way to confirm he was entitled to this was by looking at his tax returns," said Steven Wagner of Wagner Berkow LLP.

Trump won't release tax returns

That is not expected to happen soon. After initially promising to release his tax returns, Trump abruptly announced last month that he will not do so because the Internal Revenue Service is auditing multiple years of his tax returns. Trump further said he has been audited every year for more than a decade; tax experts say the probability of a taxpayer being subject to such a long succession of audits is low.

This week, Lewandowski repeated Trump's explanation for not making his tax returns public. Asked if Trump would release taxes from years in which he was no longer subject to audit, Lewandowski said, "I can't speak to that."

How much is Trump really worth?

The size of Trump's fortune and income had been the subject of considerable scrutiny and debate. Trump has claimed his fortune is in excess of $10 billion, and a personal financial disclosure he filed with the Federal Election Commission shows $362 million in income in 2014.

The income reported on the form is often not the same as the income that would be reported on Trump's personal taxes, however. Instead, many of Trump's businesses reported their gross income, meaning their total revenues.

Gross income does not include the expenses required to run a business — meaning that Trump's profits from the businesses would be far less than the $362 million. For example, his financial disclosures show a gross income of $20.3 million for Trump's golf resort in Scotland, Trump Turnberry. But the course is under renovation and ended up losing $3.2 million in 2014 after taking into account operation costs, according to U.K. corporate records.