His first stop will be in Saudi Arabia, where at least 55 world leaders and other industry leaders are expected to take part in three summit meetings in Riyadh. While it is far from a business trip, some ethics experts are concerned that Mr. Trump could approach the visit and his other diplomacy through the lens of his personal business.
“It is particularly worrisome for the president to have business with extensive involvement overseas, because we often have to make very difficult choices in dealing with situations overseas,” said Richard W. Painter, who served as a White House ethics lawyer in the George W. Bush administration and has been critical of Mr. Trump’s approach to dealing with potential conflicts of interest.
One of Mr. Trump’s sons, Donald Trump Jr., recently visited a business partner in Dubai, where the Trumps have helped build a golf course and have been planning a second, prompting questions about whether they planned new development. But his brother Eric Trump repeated Thursday that the company is adhering to its ban on new deals.
Mr. Trump has come close to a major development deal in Israel. About a decade ago, he signed a licensing deal on a 70-story Trump Tower on the outskirts of Tel Aviv. The tower was never built, and Mr. Trump sued his partners, claiming they violated their agreement.
Mr. Trump, though, viewed Israel as “one my favorite places in the world,” telling a business conference that in 2006, according to news reports. He continued to pursue partnerships there, including by teaming up with an Israeli company on a line of Trump-branded vodka and energy drinks.
Last year, his executives were discussing a deal to be a partner on a 61-story tower in Tel Aviv that would have included residences and a hotel, according to Eric Danziger, the chief executive of the Trump hotel division. But Mr. Danziger said Mr. Trump’s election had prompted the Trumps to withdraw to comply with the ban on foreign deals.
“We had to retreat, period, simply because of the election,” Mr. Danziger said. “Had he not won, we would have done” the deal.
Eric Trump, one of the Trump sons now managing the company, said in an interview in February that the Israel deal was emblematic of the new realities facing the company.
“You can’t build the tallest building in Tel Aviv and try to negotiate peace in the Middle East,” he said.
Yet Mr. Kushner, in his role as White House adviser, is leading efforts to reach a peace agreement in the Middle East, despite his company’s extensive financial ties to Israel. Hope Hicks, a White House spokeswoman, recently told The New York Times that Mr. Kushner would work with counsel to ensure he recused himself from “any particular matter involving specific parties in which he has a business relationship with a party to the matter.”
The firm he ran until January, Kushner Companies, has taken out at least four loans from Israel’s largest bank, Bank Hapoalim. The bank is the subject of an investigation by the Department of Justice over allegations that it helped wealthy Americans evade taxes with undeclared bank accounts.
Another Kushner lender from Israel, Bank Leumi, admitted in 2014 that it had conspired to help American taxpayers hide income using offshore accounts. Kushner’s firm has also worked in partnership with Harel, a large Israeli insurance company, and almost bought another Israeli insurance company, Phoenix.
Kushner Companies also bought several floors of the former New York Times building from Lev Leviev, an Israeli businessman and philanthropist.
And last month, The Times reported that the Kushners had teamed up with at least one member of Israel’s wealthy Steinmetz family to buy nearly $200 million of Manhattan apartment buildings, as well as to build a luxury rental tower in New Jersey. The family’s best-known member, Beny Steinmetz, is the subject of a United States Justice Department bribery investigation.
In January, when Mr. Kushner stepped down as chief executive of Kushner Companies, he divested his stakes in some of the entities that hold investments in the family business. Still, he held on to the vast majority of his holdings. Over all, he remains the beneficiary of a series of trusts that own his stakes in Kushner properties, and other investments, worth as much as $600 million, according to government ethics filings, and possibly even more.
The Trump Organization has said it scouted a hotel deal in Saudi Arabia in recent years but ultimately opted not to pursue it. The company had set up eight corporate entities that appeared to be linked to a Jidda, Saudi Arabia, deal in August 2015, after Mr. Trump had begun his campaign. Each of those has since been canceled.
At a rally in Alabama in 2015, Mr. Trump suggested that he had benefited from the Saudis in his residential business, saying: “Saudi Arabia — and I get along great with all of them. They buy apartments from me. They spend $40 million, $50 million. Am I supposed to dislike them? I like them very much.”
His comments and the business activity there left some critics with questions about his future business dealings with the Saudis.
“We know he has had business there, has explored deals, and we don’t know what deals he could explore there in the future,” said Noah Bookbinder, the executive director of Citizens for Responsibility and Ethics in Washington, a liberal nonprofit group. “It is certainly enough to suggest that there could be business interests on his mind when he’s there.”