The GAO pointed out that mortgage servicing rights and capital standards rules are relatively new, but financial institutions and trade groups had expressed concern that the servicing rights requirements would hurt community lenders' efforts to provide and service mortgages to their customers and members.

“Although new regulations related to mortgage lending and servicing may increase compliance costs for community banks, our analysis suggests that these lenders generally appear to be participating in residential mortgage lending much as they have in the past,” the GAO said.

The GAO cited comments from officials at one credit union, who said servicing allowed the credit union to stay in touch with members and market additional services.

The CFPB said its exemption for small servicers is a way to help keep compliance costs low. The bureau estimated 99% of banks and credit unions with less than $1 billion in assets would be eligible for a small servicer exemption that would eliminate the requirement to comply with many parts of the servicing rules.

The small servicer exemption is available to institutions that service fewer than 5,000 mortgages.

The GAO report also criticized the CFPB for not having done significant work in developing a plan on how to evaluate the new mortgage rules. That review is required under Dodd-Frank and is due in January 2019.