Washington (CNN) Commerce Secretary Wilbur Ross failed to sell a bank stock holding within the required time frame after his 2017 confirmation and subsequently signed ethics documents indicating the holding had been sold, according to a report from the Center for Public Integrity.

Ross continued to hold shares worth up to $15,000 in Florida-based BankUnited until October 2018, though he was required to divest within 90 days of his Senate confirmation in February 2017, according to documents obtained by the nonprofit

He said in a statement that he thought the stock, which represents a tiny fraction of his net worth, had been sold in May 2017. He said that the previous disclosures in which he indicated he had sold the stock were "based on a mistaken belief that the agent executed my sell order on that date."

In his statement, Ross also said that his October disclosure "corrected an earlier filing."

It's the latest in a string of similar problems for the billionaire investor.

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