NEW YORK (Reuters) - Donald Trump campaigned for president as a savvy billionaire who would apply his business acumen to improving the U.S. economy, cutting taxes for Americans and negotiating better trade deals.

Flags fly above the entrance to the new Trump International Hotel on its opening day in Washington, DC, U.S. September 12, 2016. REUTERS/Kevin Lamarque/File Photo

But his vast, complicated network of businesses under the Trump Organization, including numerous foreign investments and debts, could create unprecedented conflicts of interest when he takes the oath of office as U.S. president in January, government ethics experts said.

Federal law does not prohibit the president from being involved in private business while in office, even though members of Congress and lower-ranking executive branch officials are subject to strict conflict-of-interest rules. Lyndon Johnson, for instance, quietly managed his broadcasting businesses despite insisting publicly that he had ceased all involvement, according to his biographer, Robert Caro.

“There are no legal restrictions, no legal requirements,” said Noah Bookbinder, the executive director of the nonpartisan watchdog Citizens for Responsibility and Ethics in Washington.

But most presidents in recent decades have voluntarily placed their personal assets, including property and financial holdings, in blind trusts overseen by independent advisers to avoid any appearance of impropriety, experts said. Under a blind trust, the owner has no say or knowledge in how the assets are managed.

President Barack Obama was one exception, but his investments are mostly in broad-based index funds and U.S. Treasury notes with little chance of conflicts.

Trump’s businesses include licensing deals, hotels and golf courses around the world. During the campaign, he filed a 104-page financial disclosure statement, as required by law, that showed he had financial interests in more than 500 entities with names like China Trademark LLC and DT Marks Qatar LLC but had few details.

BLIND TRUST

While plenty of wealthy men have been president, no one has ascended to the White House with such a complex array of assets.

Trump’s spokeswoman did not respond to a request for comment on how he planned to manage his businesses while he was in the White House.

During the campaign, Trump did say he would likely transfer day-to-day operations to his children. But experts in government ethics said that would do little to insulate Trump.

“That presumably frees some time up for him to be the president, but it doesn’t do anything to clear the conflicts of interest,” said Kenneth Gross, a Washington, D.C.-based lawyer who has counseled high-ranking political appointees on ethics laws. “His family’s interests, his children’s interests, are co-existent with his own.”

The nature of Trump’s businesses, Gross said, makes a blind trust all but meaningless – even if he were inclined to shift control of his empire from his family, an idea he has rejected.

Gross advised Michael Bloomberg, a New York billionaire businessman, when he became mayor of New York City. Bloomberg stepped away from day-to-day operations at his data and media company, Bloomberg LP, and donated all terminals that were used by city agencies to avoid any impression of profiting from public funds.

Some of the potential problems for the Republican president-elect are obvious. One of his latest ventures, a luxury hotel in Washington just blocks from the White House, leases its property from the U.S. government, putting Trump on both sides of any landlord-tenant disputes.

Others are more opaque. Trump has licensing deals and diverse real estate holdings in numerous countries that could benefit from foreign government subsidies or tax breaks. Companies in which he holds an interest owe hundreds of millions of dollars in debt to foreign banks that are subject to U.S. regulations, such as Deutsche Bank and Bank of China, according to the New York Times and the Wall Street Journal.

His properties include hotels in countries like Turkey, Uruguay, the Philippines and South Korea, and golf courses in the United Arab Emirates, Ireland and Britain.

Conflicts of interest could stem, for example, from countries trying to influence policies by doing business with any of his companies or even his children. His daughter Ivanka has a line of fashion products, which along with other Trump-branded items are made in countries like China.

Trump has accused China of currency manipulation and threatened to put tariffs on its imports.

GOVERNMENT REVIEW OF TRUMP INC. DEALS?

Trump’s opponent, Democratic nominee Hillary Clinton, faced criticism during the campaign over the Clinton Foundation, the charity founded by her husband, former President Bill Clinton.

That was despite an ethics agreement that Hillary Clinton signed in 2009 in order to become Obama’s secretary state that was designed to ensure donors could not sway U.S. foreign policy. Under the deal, the State Department was allowed to review any new contributions from foreign governments.

Unlike Clinton, however, Trump is not answerable to anyone else as president. And he has already shown himself willing to blur the lines between campaigning and marketing, holding events at his own properties and touting his companies during speeches.

Given the high-profile properties that bear his name, a blind trust would do little to help his case, experts said.

“You can’t put a golf course in a blind trust; it would be pointless,” said Robert Kelner, a Washington lawyer and an expert on government ethics. “The idea behind a blind trust is that it’s blind – you don’t know what assets are held.”

The only unassailable solution, experts said, would be for Trump to sell off his businesses and place the proceeds in a blind trust.

With no legal requirements, Trump’s actions as president are only subject to the will of the voters or to built-in checks and balances like Congressional oversight.

The potential for conflicts is exacerbated by the lack of publicly known details about Trump’s holdings. Even his net worth is unclear. Trump has boasted of more than $10 billion in wealth, but financial magazines have estimated his fortune at less than half that.

He has refused to release his tax returns, breaking with decades of presidential campaign tradition, and legal experts said he is under no obligation to do so as president.

His dealings with foreign governments are thus largely unknown. He will likely face scrutiny of policy decisions that affect countries where he is known to have business interests, said Bookbinder.