BEDMINSTER TOWNSHIP, N.J. — President-elect Donald Trump gets into a vehicle at the clubhouse at Trump National Golf Club Bedminster in Bedminster Township, N.J., on Saturday, Nov. 19, 2016. (Jabin Botsford/The Washington Post)

President-elect Donald Trump has disclosed owning millions of dollars of stock in companies with business pending before the U.S. government and whose value could rise as a result of his policies.

Trump’s stock holdings, which are separate from the more high-profile real estate and branding empire that he has said he will separate from in some fashion, represent another area rife with potential conflicts of interest that Trump has yet to address as he prepares to take office.

Trump’s stock holdings, as of his most recent disclosure in May, included millions of dollars worth of shares in financial institutions such as Goldman Sachs and Wells Fargo, which have seen their stock prices rise with his promises to roll back regulations imposed after the 2008 financial crash. He has held substantial numbers of shares in Apple and a unit of Ford, companies whose executives he has spoken with since the election as part of his efforts to press corporations not to ship jobs overseas.

Trump’s portfolio also has been dotted with millions of dollars worth of shares in oil and other energy companies that could stand to gain if he follows through on promises to loosen environmental regulations and pursue more drilling — including Halliburton, ExxonMobil, Occidental Petroleum and Phillips 66.

Donald Trump has a lot of potential conflicts of interest as president – but there's no law that specifically requires a commander in chief to remove themselves from all of their business interests. The Fix's Peter W. Stevenson explains why presidents usually put their assets in a "blind trust" to avoid problems. (Peter Stevenson/The Washington Post)

“In truth, what we’re looking at is a president-elect who has a personal financial stake in every major climate battle that is going on. That is indeed a troubling conflict of interest,” said Carroll Muffett, president of the Center for International Environmental Law, which has clashed with Exxon.

Trump tweeted Wednesday that he will hold a news conference Dec. 15 to explain how he will separate himself from his own business, the Trump Organization, to avoid the appearance of a conflict — though he has continued to meet with international business partners since his election victory and acknowledged that his presidency is good for the brand.

But Trump has been silent on whether that announcement will also explain what he will do about his stocks. His May disclosure showed he held stocks that were worth as much as $40 million. A Trump spokeswoman did not respond to requests for comment.

Ethics experts said Trump could solve the matter relatively easily, as have past presidents, by selling his portfolio or placing it in a blind trust over which he had no control.

Trump’s stock portfolio presents “a smaller bore but significant example of the same problem he has with the Trump Organization,” said Norm Eisen, who served as special ethics counsel to President Obama and has been critical of Trump’s conflicts.

“Nobody will know if the decisions he’s making are influenced by the public interest or by his and his family’s personal financial interests,” Eisen said.

In recent years, Congress has showed particular sensitivity to the possible self-enrichment available to elected officials who hold stock.

Under the Stop Trading on ­Congressional Knowledge Act, or “STOCK” Act, passed in 2012 on a near-unanimous bipartisan vote and signed into law by Obama, elected officials are forbidden from using non-public information they learn through their official positions to guide stock transactions. They must also publicly disclose any stock trades worth more than $1,000 within 45 days of the transaction.

The law applies to members of Congress as well as to the president and vice president and other officials, though it specifically excludes certain categories of assets, including real estate and the holdings of blind trusts.

Experts said the new law, while extraordinarily narrow, may provide one of the only regular opportunities for the public to see how Trump is handling his private business interests as president, were he to continue trading on the stock market after taking office.

Under conflict-of-interest laws, presidents are otherwise required to provide information about their public finances only once a year. Because Trump filed a financial disclosure as a presidential candidate in May, he will not be required to outline his private holdings again until May 2018, when he will report his 2017 finances.

Trump, more than any other modern president, will test the system of disclosure. Not only does he enter office after building a large and sprawling business and substantial investments, but he also has demonstrated an unwillingness to be transparent by refusing to release his tax returns, breaking with four decades of tradition during the campaign. There is little expectation Trump will release his tax returns as president, either.

Peter Schweizer, a conservative author whose 2011 book “Throw Them All Out,” about stock trades by members of Congress, helped inspire passage of the new law, called on Trump to use the STOCK Act’s model of frequent disclosure to guide voluntary disclosures about other aspects of his business.

“Transparency is the best antidote to corruption,” said Schweizer, who has worked closely with Trump senior adviser Stephen K. Bannon. As president of a group Bannon chaired, Schweizer wrote “Clinton Cash,” which alleged that Hillary Clinton faced potential conflicts of interest because of donors to her husband’s foundation.

The lack of regular disclosure makes assessing Trump’s stock holdings as he enters office difficult. Trump’s stock portfolio, as disclosed in May, was full of possible areas of conflict. However, he told Fox Business News in August that he was dumping stocks because he predicted the market was crashing. “I did invest, and I got out, and it was actually very good timing,” he said then.

Trump spokeswoman Hope Hicks did not respond to questions about whether Trump indeed sold stocks at the time. In the interview, he also predicted the market would improve if he won.

So far, Hicks has confirmed only one Trump trade since his last legally required disclosure. Over the summer, she said Trump sold his shares in Energy Transfer Partners, the majority stakeholder in the $3.7  billion Dakota Access pipeline project that has drawn protests from environmentalists and Native Americans. They have hoped the federal government will intervene in support of their opposition.

Trump had disclosed in May 2015 that he owned between $500,000 and $1 million worth of stock in the company. Candidates are required to disclose such holdings only in broad ranges. By May 2016, when Trump updated his annual filing, the value of the holding had fallen to less than $50,000. The company’s chief executive was a major campaign donor to Trump, but its stock had declined in value in the face of protests.

Hicks has declined to explain whether Trump sold the stock to shed himself of a potential conflict or for another reason, nor would she disclose whether he has sold his stock in Phillips 66, which also owns a stake in the pipeline. Trump has disclosed his Phillips 66 stock was worth as much as $250,000.

According to Trump’s May disclosure, he owned between $50,000 and $100,000 in oil-services giants Halliburton and ExxonMobil, and between $500,000 and $1 million invested in Occidental Petroleum, one of Texas’s biggest oil producers.

He also disclosed that he owned up to $30,000 in stock in oil-pipeline giant Kinder Morgan. He listed additional holdings in Chevron and Shell.

Trump’s deep portfolio could allow him to directly benefit from global events. A broad oil-production deal reached this week by the Organization of the Petroleum Exporting Countries, or OPEC, sent global oil prices climbing and boosted share prices for all of Trump’s oil-company stocks.

Among Trump’s other holdings, according to his May disclosure, were between $1.1 million and $2.2 million in stock in Apple, the tech giant he urged Americans to boycott during the campaign.

In an interview with the New York Times last week, Trump said he got a call from Apple chief executive Tim Cook, and he recalled telling Cook that it would be “a real achievement for me” if Apple built “a big plant” in the United States.

Trump said he told Cook: “I think we’ll create the incentives for you, and I think you’re going to do it. We’re going for a very large tax cut for corporations, which you’ll be happy about.”

Apple did not respond to requests for comment.

In the disclosure, Trump said he had stock worth $500,000 to $1 million in the consumer-lending units of both Toyota and Ford, the latter of which Trump loudly criticized for outsourcing factory jobs to Mexico.

Shortly after the election, Trump took credit for persuading Ford to save a car-making plant in Kentucky, rather than move it to Mexico. Ford later said it had not planned to move the plant, only one production line, and that the original plan would not have led to any lost American jobs.

Trump also owned between $1.1 million and $2.2 million in AT&T stock. Trump has criticized the company’s proposed acquisition of Time Warner, which owns CNN, as “an example of the power structure I’m fighting,” but he has also formally named technology advisers with a history of support for media mega-mergers and distaste for regulation.

Trump, meanwhile, owns up to $1 million in stock in media conglomerate Comcast, one of AT&T’s biggest rivals.

Wall Street banks have made up a large share of Trump’s stock holdings.

Trump also owns between $500,000 and $1 million in shares each in Morgan Stanley, Citigroup, Goldman Sachs and Wells Fargo, the latter of which is now facing federal investigation after a scandal involving millions of unauthorized bank accounts.

One of those banks, JPMorgan Chase, the largest bank in the United States, agreed last month to $264 million in fines to settle federal charges that the bank had given lucrative jobs to friends and family members of Chinese government officials as a means of bribery.

Already, financial industry stocks have seen dramatic improvement since Trump’s election, said Jamie Cox, managing partner of the Harris Financial Group, in anticipation of a rollback by Trump and a Republican Congress of regulation imposed after the 2008 financial crash that’s likely to continue after Trump takes office.

“You’ve seen them skyrocket,” he said. “It’s one of the hottest sectors.”

Anu Narayanswamy contributed to this report.