The fiduciary rule was published in the Federal Register in April of 2016, and it has a June 8, 2016 effective date. In the eyes of the law, the meaning of "effective" date is different from the meaning of the implementation or applicability date of a rule, which in the case of the fiduciary rule is April 10.

"The rule is effective, even though the compliance date is still out there, and that means the rule is in effect—it is the law," said Leland Beck, an administrative law expert who previously worked in the Department of Homeland Security and Justice Department.

If Friday's White House memo is interpreted as a directive to delay implementation of the fiduciary rule, there is the possibility that it could be subject to a legal challenge under the Employee Retirement Income Security Act's private right of action clause.

Beck says that potential development would be without precedent. "I don't know of any cases where a compliance date was delayed, and then a private actor sued. That underscores the uniqueness of the situation with the fiduciary rule. The law does not answer all of these questions."

Other options in the hopper

Jason Roberts, CEO of the Pension Resource Institute and the founding attorney of the Retirement Law Group, has heard–but has been unable to verify– the Trump administration is also planning to send a separate document from Friday's memo, directing the Labor Department to review the fiduciary rule.

Roberts' sources have also said Trump's Labor Department will use existing legal precedent to delay the rule for six months until ongoing litigation over the rule is resolved in federal courts in Texas, Kansas, and Washington D.C.

A separate proposal to delay the rule for one year will be issued by Labor, according to Roberts' sources, which will be subject to a 14-day notice and comment period.

And on top of those efforts, Labor's new leadership is expected to separately propose to withdraw the rule, which would also be subject to a notice and comment period, for the purpose of replacing the rule.

Roberts says the first two options to delay the rule could come any day, and that he believes his sources to be credible.

If reports of the multi-pronged approach to delaying and possibly amending the rule are true, it would certainly put to rest speculation the Trump administration feels ambivalence for a rule that is expected to impact trillions of dollars in retirement savings in the coming years.

Rather, if true, the strategy would suggest a delay is imminent and will come soon, and that any rule implemented under the Trump administration could look substantially different from the one industry has invested tens of millions to comply with.

All-agency memo needs further clarification

Barbara Roper, director of investor protection at the Consumer Federation of America, which advocated for the rule in its current form, says the legal team at CFA does not believe Friday's agency-wide memo covers the fiduciary rule, given that its effective date has passed.

"At the very least, I think firms weighing what to do about compliance would want clarification on that point," said Roper in an email.

"If the Trump administration were to try to delay the rule through the regulatory process without going through the appropriate, legally required notice and comment, we and others would have to seriously consider filing a legal challenge," she added.

The decision to move forward with a challenge won't be made until the new administration fully reveals its course of action, said Roper. "It is essential that government agencies follow the same rigorous procedures when they seek to roll back regulations that industry demands when they seek to strengthen regulatory protections."

Erin Sweeney, who served as an attorney in the Employee Benefits Security Administration under the George W. Bush administration, said there is precedent for delaying rules until existing legal challenges run their course.

But Leland Beck suggested in the case of the fiduciary rule that strategy may also be subject to dispute.

"There is a provision in the Administrative Procedure Act that says an agency can stay the effective date of a rule in the interest of justice if there is pending litigation," said Beck. "But does this apply to the implementation date of a rule? Again, that is unclear."

Trump administration must weigh regulatory technicalities

The fact that the fiduciary rule's implementation date is different from its effective date raises technical regulatory questions.

"There is no simple answer to whether to Trump administration can halt the fiduciary rule or any other rule that is already published," said Beck. "If the effective date has passed, the rule can only be changed by another rule."

Because the fiduciary rule's compliance date applies to private legal actions to enforce the rule, Beck says the Trump administration's ability to change the compliance date will depend on language in the Code of Federal Regulations, the official codification of regulations published by the Federal Register.

If the compliance date is already published in the CFR, then changing the date will require another rule.

But if it has yet to be officially published in the CFR, then the Trump administration may have more latitude to delay the implementation date. Beck said the distinction "is not clear."