Attorney General Martha Coakley is investigating Santander for its underwriting and securitization of subprime auto loans.

"We are specifically concerned about trends that show an increase in the prevalence of sub-prime auto loans at the same time that more borrowers fall behind on their payments. We are using our experience, gained in holding banks responsible for unfair and predatory mortgage loans, to ensure consumers are protected in other areas of lending," said Brad Puffer, a spokesman for Coakley’s office.

Puffer confirmed that Coakley is one of "various state Attorneys General" said to have subpoenaed the company in Santander’s latest quarterly filing with the Securities and Exchange Commission. Santander also acknowledged a civil subpoena from the Department of Justice requesting similar information and said in the filing that it is complying with those requests.

More broadly, regulators have recently been concerned with auto lending practices similar to those that preceded the subprime mortgage crisis and subsequent economic recession. Regulators and state attorneys general have turned their eyes toward higher rates of defaults on auto loans, underwriting, securitization and other potentially sketchy practices, like title loans and automatic shutoffs.

Puffer said that Coakley’s office is investigating a number of other auto lenders, but did not name any of the other parties. He also cautioned that the mere fact of the subpoena does not imply wrongdoing.