"We have been committed to making changes and improvements based on public comment and feedback, but cannot say to what extent the final rule will differ from the proposal," a Labor Department spokesperson told Reuters.

The agency reviewed comment letters and live testimony from industry officials in support of and against the rule. In January, the revised proposal was sent to the White House's Office of Management and Budget.

Ahead of the rule's introduction, some firms are trying to a avoid losing accounts by cutting fees and reducing the minimum balance that clients need to have.

While some opponents have said the rule will force them to abandon clients with small accounts, others are opting to adjust their account offerings and include lower-cost, fee-based accounts.

St. Louis-based firm Edward Jones is piloting low-cost accounts and charging an annual fee for clients with a minimum of $5,000. Normally, customers have to have $50,000 in a fee-based account.

LPL Financial Holdings said this week it would allow clients to maintain less money in their brokerage accounts and cut fees in preparation for the rule.

Straw That Breaks The Camel’s Back

Small wealth management firms are expected to take the biggest hit after the rule goes into effect because they have fewer resources to pay for extra paperwork, training and new technology needed to comply.

As firms redirect resources to ensure they are compliant, some advisors worried about lower commissions and compensation have begun to ask recruiters about new opportunities.

"The rule isn't the sole reason people are ready to move, but in every conversation we have, it is discussed because advisers will be impacted," said Louis Diamond, vice president of Diamond Consultants, a New Jersey-based recruiting firm. "For advisors who are already unhappy, the rule could be the straw that breaks the camel's back."