People tend to think of banks and other lenders as the main users of credit reports. But over the last several decades, credit reporting bureaus have been selling their services to a much wider range of buyers.

“Credit reports are really seeping into the soil,” said Sarah Ludwig, co-director of the Neighborhood Economic Development Advocacy Project, a New York-based nonprofit. “It’s taken an outsized role in employment, housing and insurance.”

For those seeking a job, it can lead to what Chi Chi Wu, a staff lawyer at the National Consumer Law Center in Boston, calls “a bizarre, Kafkaesque experience.”

“Someone loses their job,” Ms. Wu said, “so they can’t pay their bills—and now they can’t get a job because they couldn’t pay their bills because they lost a job? It’s this Catch-22 that makes no sense.” It can also be a kind of backdoor job discrimination, Ms. Wu contends, given the numerous studies that demonstrate that those black, Latino or simply poor are more likely to have lower credit scores than those who are white and have means.

Experian, one of the big three credit reporting bureaus, states in its marketing materials, “Credit information provides insight into an applicant’s integrity and responsibility toward his or her financial obligations.”

But to Ms. Wu and others, a credit report says more about a person’s economic circumstances than his or her moral character. “Some people can go to daddy and say, ‘I can’t pay my bills, will you bail me out?’” Ms. Wu said. “And others can’t.”

Terry W. Clemans, executive director of the industry group National Consumer Reporting Association, underscores the credit bureaus’ pitch: “Does this consumer have a lifestyle that fits the job? Is this someone who I can trust?” But consumer advocates say there is little evidence of a link between a person’s credit score and trustworthiness. Even an official from TransUnion admitted in a 2010 testimony that “we don’t have any research to show any statistical correlation between what’s in somebody’s credit report and their job performance or their likelihood to commit fraud.”