Trump sold all of his stock earlier this year, a spokesman said.

Transition team did not provide proof of sale, explain sell-off.

President-elect Donald Trump sold all of his stocks in June as he plunged into the costly general election campaign, his transition team abruptly announced Tuesday.

His advisers provided no proof of the transactions and would not explain the apparent sell-off.

The announcement comes amid questions about potential conflicts of interest between Trump’s expansive financial holdings and the decisions that will reach his desk as president. Some details of Trump’s finances are unknown given that he never released his tax returns during the presidential campaign, breaking decades of precedent.

On Tuesday, Trump said the government should cancel its multibillion-dollar order with Boeing for new Air Force One presidential planes. Asked on a conference call with reporters whether Trump had investments in Boeing, spokesman Jason Miller said the president-elect had sold all of his stocks in June.

Trump’s campaign did not announce the sell-off at the time, despite the fact that it could have been politically advantageous for the businessman to be seen taking steps to avoid potential conflicts of interest. Miller, as well as other transition officials and lawyers from the Trump Organization, did not respond to requests to provide evidence of the transactions. As of May, Trump reported owning millions of dollars’ worth of individual stocks, though he had more money in company-specific investments through bonds, mutual funds and private equity investments, according to his 104page public financial disclosure, which all presidential candidates are required to file. Trump reported in May an investment in Boeing worth between $50,000 and $100,000. Other investments were in companies — such as Ford Motor Co., V F Corp. and Thermo Fisher Scientific — that in recent years have moved jobs outside the U.S., a practice that Trump heavily criticized during the campaign. The disclosure also showed Trump held a small amount of stock in Texas-based Energy Transfer Partners and at least $100,000 in the energy company Phillips 66, both of which are involved in the disputed Dakota Access oil pipeline.