Robo-calls ravaged Americans’ smartphones in record numbers last month. But some of the nation’s top businesses — from credit card companies and student lenders to retailers and car dealers — are still urging the Trump administration to make it easier for them to dial and text mobile devices en masse.

For many smartphone owners, there’s rarely a day that they don’t receive an unanticipated call from an unrecognized number, some sporting an area code that’s suspiciously similar to their own. In June, robo-calls rang an estimated 4 billion times, according to data published Thursday by YouMail, a call-blocking app. A quarter of the calls sought to steal financial information or ensnare people in other serious scams.

But major U.S. corporations such as Capital One, Navient and Sirius XM tap that same auto-dialing technology to tout their products or nudge consumers to pay their late bills. Their lobbying blitz to ward off tougher new rules has frustrated public-interest advocates, who say the floodgates soon could be open for businesses to pester consumers with calls and texts that they don’t want — while leaving people with fewer options to stop the onslaught.

"We are at serious risk of seeing the existing robo-call problem, which is already serious, get far, far worse,” said Margot Saunders, a senior attorney at the National Consumer Law Center. “If the industry is permitted to send unlimited texts and make unlimited [robo-calls], without the ability of the consumer to say stop, who knows what horrible things will happen?"

The new data from YouMail marks the highest level of robo-calls the company has ever calculated and the fourth time a record has been broken in as many months. About three-quarters of those calls were telemarketing calls, alerts from companies such as pharmacies with which consumers have a relationship and payment reminders from numbers associated with Capital One, Comcast, Wells Fargo and AT&T, the data shows.

The increases are partly due to the fact consumers are answering their phones less frequently, so callers are adopting more aggressive tactics, said Alex Quilici, the chief executive of YouMail.

The task of regulating these robo-calls rests in the hands of the Federal Communications Commission, which is studying the matter in response to a recent court decision that struck down the agency’s last set of protections. The FCC declined to comment for this report.

But businesses led by the U.S. Chamber of Commerce have warned that potentially onerous new federal rules on whom they can contact and how they contact them would prevent companies from providing useful information to consumers while opening the door to a raft of new lawsuits.

"What we have heard … is that it has chilled ways of trying to communicate with consumers, whether you’re an insurance company trying to tell a customer your homeowner policy is expiring or you’re CVS saying your prescription is ready,” said Harold Kim, a senior vice president at the U.S. Chamber’s Institute for Legal Reform.

What actually counts as a robo-call — and how the federal government plans to regulate it — is the subject of political and legal disputes. Under a 1991 law passed before the arrival of iPhones and Androids, the FCC imposed tough restrictions on any technology that randomly generated and dialed phone numbers. Those who use auto-dialers had to obtain a customer’s explicit permission to contact them, too.

But the tools to auto-dial numbers have evolved and proliferated dramatically, prompting the government to tweak its definition of robo-calls — though not without opposition. In 2015, the FCC adopted rules that covered more technologies and opened the door for consumers to bring more lawsuits against entities that ignored their demands to stop calling. In response, a trade association of debt collectors sued the agency, claiming its rules were too broad, and a federal court in March agreed.

Under the Trump administration, the FCC again has solicited policy ideas from consumer and industry groups. In the process, corporations have pushed back on rules that would target them or mean stiff penalties if they make mistakes.

The Institute for Legal Reform, for example, urged the FCC in May to define what qualifies as a robo-call so that virtually any intervention from a human — and the use of call lists to contact consumers systematically — would not qualify under the law. Because those calls may not technically be considered “robo-calls,” businesses may not have to obtain consent in some cases to contact a consumer in the first place, opponents contend.

Maureen Mahoney, a policy analyst at Consumers Union who has testified to Congress about robo-calls, described such efforts as attempts “to chip away at the protections that consumers currently have.”

"What's particularly concerning is that consumers wouldn't have the legal right to demand calls [under the law] to stop,” she said.

Student lenders such as Navient, backed by well-heeled Washington trade associations, have lobbied just as aggressively, telling the FCC that robo-call restrictions stand in the way of their “ability to help at-risk and disadvantaged student loan borrowers.” In effect, they asked the FCC in June to adopt rules that could spare the industry from more lawsuits in cases where they are acting in good faith to try to collect a debt yet reach the wrong number, according to the National Consumer Law Center.

A key voice for the industry, the Student Loan Servicing Alliance, stressed that lenders have “no interest in and get no benefit from calling the wrong person,” said Winfield Crigler, the executive director of the group.

Yet Navient has been a frequent target of complaints — and lawsuits — alleging it has harassed consumers with debt-collection robo-calls. Last month, even as Navient asked the FCC to overhaul its rules and reduce robo-call lawsuits, it agreed to pay $2.5 million to settle a class action case brought by a Virginia woman who argued the company repeatedly contacted her about a debt her brother owed.

Nikki Lavoie, a spokeswoman for Navient, said the company doesn’t “agree with the allegations.” She argued the case offered “another example of how the law needs to be reformed.” Capital One and Sirius XM did not immediately respond to requests for comment.

As the FCC figures out how to rethink the robo-call rules, the agency’s chairman, Ajit Pai, has focused his efforts on combating fraud and abuse. In May, the FCC imposed a record $120 million fine on a Florida man responsible for millions of unwanted, automatically dialed calls. Pai has called such calls a “scourge."

The FCC along with its sister agency, the Federal Trade Commission, even has tried to nudge the telecommunications industry to create new technologies that might block robo-calls behind the scenes. And companies such as YouMail have introduced their own call-blocking services.

But there are forces in and outside government that believe the FCC needs to take broad, aggressive action to thwart a wide array of robo-calls at a moment when such interruptions are on the rise.

Sen. Edward J. Markey (D-Mass.), for one, said Thursday that a weakening of federal robo-call rules means “powerful industries stand to benefit from increased bombarding of consumers with relatively inexpensive calls — calls for marketing, advertising, and debt collection.”

“The formula is simple,” he said in a statement, “more inexpensive calls and less legal liability equal bigger profits for corporations.”