They were also equally sure that the rule's breadth and complexity will create new compliance costs and challenges.

Here is a snapshot from a handful of publicly traded providers, which of course are required under securities law to address regulatory impacts on company revenues to stockholders.

The below quotes are taken from audio of the earnings calls, or from transcripts provided by Seeking Alpha. Minor adjustments are made to quotes to account for malapropisms in the transcripts.

1. MetLife

In February, MetLife announced it was selling its retail advisory unit to MassMutual. In a release, Steven Kandarian, MetLife's CEO, said "By decoupling manufacturing from distributions, our U.S. retail business will be more agile, and both MetLife and the U.S. retail business can achieve significant cost savings."

In its latest earnings call, Eric Thomas Steigerwalt, CEO of MetLife Insurance Company of Connecticut, told analysts the sale to MassMutual is expected to close by this July, well before the first of two deadlines for the DOL rule's implementation—the first deadline is April 10, 2017.

MetLife will, however, continue to generate investment and annuity products, which will be distributed through its wholesaler channel. That raises the question of whether MetLife, and other manufacturers of investment funds and annuities, will be subject to the rule's Best Interest Contract Exemption provision.

"It's just too early to know where distributors are coming out with respect to the regulation. So, maybe four months or five months from now, we'll have a better view of that, but right now given the fact that this [DOL rule] is almost 1,100 pages, we're just going to have to wait and see what a number of distributors are going to do," said Steigerwalt.

Under the rule, advisor recommendations of variable and fixed indexed annuities will be subject to the BIC exemption. What restrictions wholesalers of those products will face requires further clarification from DOL, implied Steigerwalt, according to the transcript from Seeking Alpha.

2. Voya Financial

In its earnings call, leadership at Voya Financial said the final rule will be "manageable" for the firm to negotiate, and perhaps may even create opportunities for the firm.

"The final rule is improved in many ways, though it still may make it more difficult for some consumers to receive advice from advisers with respect to certain situations such as IRA rollovers," said Rod Martin, CEO of Voya Financial.

"The rule could have implications for certain of our distribution partners, such as possibly requiring advisors to partner with larger firms or cease to sell certain products," he added.

As a recordkeeper to 401(k) plans, Martin said Voya will be largely unaffected by the rule, which will require advisors to plans with less than $50 million in assets to act as fiduciaries. As far as the small and midsize plan segment is concerned, Martin said Voya already operates in accordance with the rule's standards.

Charles Nelson, CEO of Voya Retirement, noted Voya uses a Morningstar fiduciary service to help plan sponsors choose underlying funds, and that that makes Voya "well positioned for future growth in the smaller and midsize market."

Nelson did say the rule will impact the IRA market industry-wide. "A lot of people in the industry believe (the rule) may result in a lot of money staying in-plan and potentially slow the growth of IRAs. Some advisors may not focus on the IRA market as much as they have in the past."

Smaller advisory firms will be challenged by the cost of complying with the rule, said Nelson, and that may be an advantage to Voya's retail advisory arm.

Voya also expects its annuity business will be able to survive the DOL rule. "We have consistently applied an approach to designing products with reasonable compensation," said Alain Karaoglan, CEO of Retirement and Investment Solutions at Voya. "We also don't engage in nonmonetary sales incentives that are prohibited by the rules."

3. Charles Schwab

"We don't expect these changes to have a meaningful negative impact on our business and there is some potential for positive benefit, although I think we are fairly cautious around that," said Walter Bettinger, CEO of Charles Schwab Corp.

Schwab's executives were not willing to project added revenue numbers from the rule.

"It's just too early to see how firms who might be more impacted by the regulation will determine how to deal with it," said Joseph Martinetto, Schwab's CFO. "I would be surprised if firms will choose to give up market share very readily, as opposed to maybe giving up a little bit of their economics."

Martinetto said he doesn't expect the final rule will accelerate the exodus to passively managed investment options in RIA channels, largely because "that has already played out over the last 10 years."

He also said he doesn't expect to see massive amounts of assets leave traditional firms for new, stand-alone robo-advisory providers, as most firms have their own robo offerings in place.

Schwab's leadership said it is unclear if the firm's existing fees on services will qualify for the DOL rules level fee exemption. Schwab has built its brand as a discount provider of investment services.

"It's too early for us to say whether the level-fee exemption could apply for us," said Bettinger. "But it's certainly one of the things we are looking at."

4. Raymond James Financial

The DOL's 1000-plus-page rule is more a guideline, and "very hard to interpret," Paul Reilly, CEO of Raymond James, told analysts in the firm's earnings call.

"No one really understands the full impact yet," he added.

What can be expected is increased compliance costs, and for retirement investors, that "won't be free," said Reilly.

"There's no free lunch here," he added. Even if commission-based brokers and advisors move clients to a fee-based account in order to comply with the rule, advisors will be making a "fiduciary move" under the BIC exemption.

"The problem in the rule is you are almost caught no matter what you do," said Reilly.

Even with respect to the grandfather provision, initially viewed as favorable by many stakeholders, Reilly explained that as soon as anything is changed to an existing account, be it compensation structure or a new investment, the account effectively becomes "ungrandfathered."

Increased compliance costs and liability risk are likely to adversely impact smaller firms that may struggle to survive after the rule is finally implemented.

"We're not hoping regulation drives them out of business, but if they make the determination that it's too costly and they want to join someone who is of like-minded culture, we would welcome them," said Reilly.

 "I'm not sure that's a good result for the industry," he added.

5. Prudential Financial

Like many of the largest plan providers, the DOL rule impacts multiple core areas of Prudential's business.

Prudential Advisors will be impacted by the BIC exemption, which advisors are expected to need to recommend proprietary products to IRA investors.

"Compliance and business processes will change, and we'll be ready for those changes," said Stephen P. Pelletier, COO of Prudential's U.S. Business Unit.

"And we fully expect that unit to continue to play an important role in our distribution strategy," he added.

For its annuity business, Pelletier addressed the "reasonable compensation" requirement on the final rule, which is expected to impact how variable and fixed indexed annuities are marketed.

"What that means will play out over time," he said. "It's still premature to offer any predictions as to what that impact will be. That's going to play out over multiple years through the lens of advisor behavior and firm behavior."

As a manufacturer of annuities, Robert Falzon, Prudential's CFO, said he does not expect Prudential will be a signatory to the BIC exemption, but as a manufacturer, the firm will be expected to support advisors in fulfilling their new fiduciary obligations.

Prudential Retirement, the recordkeeper arm of the larger business, focuses on the large-plan market, said Pelletier. The final rule's clarification on the difference between participant education and advice—which allows greater latitude in offering example asset allocation models relative to language in the proposed rule—is a welcomed improvement, he said.