A November executive order by former President Donald Trump banning U.S. investment in companies with ties to the Chinese military has proven difficult for compliance officers to navigate.

On the surface, the order seems straightforward: starting Jan. 11, U.S. investors are barred from investing in the named entities; by Nov. 11, American investors must divest from any stake in the blacklisted companies.

But complying with the order has proven problematic for a number of reasons.

For one, a week before he left office, Trump added eight more companies to the blacklist, bringing the total named entities to 44. The Office of Foreign Assets Control (OFAC) advised the New York Stock Exchange (NYSE) the blacklist includes China Mobile, China Telecom, and China Unicom (Hong Kong) Ltd., which were not included on the original list of blacklisted companies.

The NYSE flip-flopped on delisting the companies, a reversal from an earlier announcement that it would not delist them, which came days after saying it would delist them.

Many of the issues investors, banks, and advisors have with complying with the order stems from this kind of lack of clarity, according to practitioners attempting to interpret the original executive order, the follow-up order, and the OFAC guidance.

Usually, a blacklist would operate under an OFAC rule that all subsidiaries of the blacklisted companies—defined as companies that are more than 50 percent owned by the named company—are subject to the blacklist. But it wasn’t clear in the executive order whether the rule applied. So, are subsidiaries covered? What about related companies? What about companies with a name that “closely matches” covered entities, as OFAC said in a Dec. 28 answer to a frequently asked question?

“There remains a number of major discrepancies and uncertainties in how to apply these restrictions,” said Justine Walker, head of global sanctions and risk at ACAMS, the Association of Certified Anti-Money Laundering Specialists. She said the order and subsequent answers from OFAC have lacked clarity.

“In short, the industry is still working through ‘who’ and ‘what’ is subject to these sanctions,” she said.

Brian Fleming, a member of Miller & Chevalier whose practice focuses on investigations and compliance counseling dealing with international trade and national security, described the Trump administration’s blacklist on U.S. investment in Chinese military companies as “a bit unorthodox.”

“It has left a lot of questions and a lot of gaps,” he said. “Right now, this is a true gray area.”

Adding to the potential for confusion is the fact Joe Biden was sworn in as President on Wednesday. Biden promises to issue a flurry of executive orders on a number of topics in his first days in office but isn’t likely to get to this one anytime soon.

Fleming said the Trump administration’s motivation for creating the blacklist is based on a central, long-standing tenet of U.S. national security policy: China is a threat, as is anything the U.S. perceives is aiding China’s continuing military buildup.

Even so, the Trump administration’s action is part of a pattern of unorthodox behavior when it comes to sanctions, Fleming said, which includes actions against TikTok and WeChat, and more recently, Alipay and WeChat Pay.

“Those were examples of the same general problem that this administration has used unorthodox methods to try to address,” he said.

Walker said different approaches to compliance might lead to different conclusions as to which entities are covered and expose them to potential liabilities for remaining invested in blacklisted organizations.

“With varying approaches for determining who is subject to these sanctions, there is the possibility of inconsistency in application. This may increase the risk of unintentional exposure,” she said. “Additionally, there are wider aspects which depart from the normal approach to sanctions and which are also being digested.”

The saving grace, she said, is the unusually long wind-down period for divesting from the companies through Nov. 11.

Fleming said the lack of clarity is causing investors, banks, and advisers to be “even more conservative than perhaps OFAC even intended.”

“A lot of people are just going to stay very far away from the line, when where the line is exactly is so murky,” he said.