HSBC, Deutsche Bank and UBS Group collectively paid just under $47 million to settle civil charges of market manipulation with the Commodity Futures Trading Commission, but gained a waiver from a rule in the Dodd-Frank Act. Mike Segar/Reuters

Three big banks were punished for market manipulation this week — and tucked into the punishment was a single sentence that could pay big dividends for the banking industry.

Under the 2010 Dodd-Frank financial regulation law, banks that violate financial rules are disqualified from access to a streamlined process for certain types of business they conduct, unless they receive a waiver from federal regulators.

That provision, known as the bad actor rule, was created to make legal settlements with regulators riskier and more financially painful for banks — an incentive for them to avoid the conduct that precipitates such settlements.

On Monday, the Commodity Futures Trading Commission reached settlements with Deutsche Bank, HSBC and UBS Group for a type of market manipulation called spoofing. The banks collectively paid just under $47 million to settle the civil charges without admitting or denying any wrongdoing.

But while the commission and Justice Department trumpeted their crackdown on market manipulation, the settlements included language that gave all three banks an automatic waiver from the bad actor rule — drawing sharp criticism from one Securities and Exchange commissioner, a Democrat.

“I am extremely disappointed by the C.F.T.C.’s actions in this case,” the commissioner, Kara Stein, said on Thursday. “They did not consult with the S.E.C. before injecting themselves into securities markets in which they have little or no expertise. The implications of the C.F.T.C.’s actions are deeply troubling and may put U.S. investors at risk.”

Erica Elliott Richardson, a spokeswoman for the C.F.T.C., said granting the waivers lets the agency reach settlements with the banks more quickly. Otherwise, she said, the banks would have wanted to apply for waivers from the bad actor rule before finalizing and announcing the settlement agreements.

Industry observers said the automatic waiver is one of the latest efforts by the Trump administration to soften regulation of Wall Street, which Republicans and some Democrats believe has gone too far.

J.W. Verret, a professor at George Mason University’s law school, said the C.F.T.C.’s move relieved banks of a burden they never should have faced in the first place.

“Outside of the partisan back and forth and outside of the cheap rhetoric about this issue, the reality is it’s very difficult to apply criminal and civil liability concepts for individuals to large multinational institutions,” he said. “That’s what underlies this whole controversy.”

Senator Elizabeth R. Warren, Democrat of Massachusetts, has been a vocal critic of Wall Street. Now, however, regulators in the Trump administration “simply feel less threatened” by her, a Columbia professor said. Erin Schaff for The New York Times

Either way, the change is expected to benefit Wall Street.

“It’s very positive for the banks,” said Therese Doherty of Mintz Levin, a lawyer who represents financial institutions in regulatory matters.

Representatives of HSBC, Deutsche Bank and UBS declined to comment.

The Securities and Exchange Commission oversees the sale of securities like stocks and bonds. A longstanding rule permits well-known sellers, like the large banks, to bypass an enormous amount of paperwork that normally would be required for new securities sales.

Under the Dodd-Frank law, banks that commit crimes or are punished by regulators for knowingly engaging in misconduct stand to lose the privilege of bypassing the paperwork. The extra work can cost millions of dollars and delay new securities offerings for months or even years, stymying their clients’ attempts to raise money by issuing stocks or bonds.

They can avoid that fate by applying for a waiver from the Securities and Exchange Commission. Regulators generally agree that the S.E.C. should grant such waivers liberally, because the alternative — handcuffing the world’s biggest banks — could have a detrimental impact on their large corporate clients, which employ hundreds of thousands of people and generate crucial economic activity.

The waivers used to be granted automatically. But in mid-2015, the commodities trading commission ended the practice. The decision followed public criticism from Ms. Stein and Senator Elizabeth Warren, a Massachusets Democrat and leading advocate for tougher regulation of Wall Street, who said the automatic waivers were an unwarranted sop to badly behaving banks.

That change wasn’t catastrophic for the banks. It simply meant they had to apply to the Securities and Exchange Commission for the waivers — which were always granted.

In December 2016, for example, Goldman Sachs Group agreed to pay $120 million to settle a C.F.T.C. case over manipulation of a derivatives benchmark. The agency did not grant an automatic bad actor waiver as part of the settlement. Instead, Goldman had to go to the S.E.C. The bank’s lawyers told the commission that it would be “extremely harmful” to the bank if its market privileges were revoked. The S.E.C. granted Goldman’s request for a waiver.

Ms. Elliott Richardson said forcing banks to wait for waivers had kept the C.F.T.C. from finalizing settlement agreements. “The S.E.C.’s waiver process has taken up to nine months,” she said. “In these cases, this has delayed C.F.T.C. enforcement actions, which otherwise would have been resolved, for almost a year.”

A Securities and Exchange Commission spokeswoman declined to comment.

On Thursday, when she learned of the C.F.T.C.’s decision, Ms. Warren said: “It amazes me that there are still Republican officials who believe the lesson of the past decade is that federal regulators have been too hard on financial firms that break the law.”

Kathryn Judge, a Columbia Law School professor, said the change was a sign of the waning influence of Ms. Warren.

“Elizabeth Warren has done an outstanding job for a long period of time being simply so vocal and so visible and understandable to the public that the administration and regulators were scared to take action that would have invoked her ire,” Ms. Judge said.

Regulators in the Trump administration, however, “simply feel less threatened by Elizabeth Warren as a figure,” she said.

Correction: February 1, 2018

Because of an editing error, an earlier version of a picture caption with this article misstated which regulator reached settlements with three banks. It was the Commodity Futures Trading Commission, not the Securities and Exchange Commission.