The Consumer Bankers Association, a trade group whose members include some of the largest lenders in the federally guaranteed student-loan program, has issued a code of conduct governing its relationship with colleges and borrowers.

Under the nonbinding “Education Loan Customer Commitment,” the association promises not to provide “anything of value” to colleges, their employees, or their affiliates “in exchange for a commitment of any kind,” and to “not engage in marketing practices” that could create a conflict of interest for college employees.

The statement also promises that lenders will “fairly and accurately” disclose the terms and conditions of their loans, while encouraging borrowers to exhaust their federal loan eligibility before taking out private loans.

The release of the “commitment” comes amid an expanding investigation into kickbacks and conflicts of interest in the student-loan industry. Just on Tuesday, Wells Fargo became the latest lender to pledge to observe a code of conduct prepared by the New York attorney general, Andrew M. Cuomo, who has spearheaded the investigation.

Joe Belew, the association’s president, said his group was “seeking to continue the well-earned public trust” in the guaranteed-loan program. —Kelly Field