Some of the nation’s biggest banks may be so big that their size prevents federal prosecutors from holding them criminally accountable for their role in the largest financial crisis since the Great Depression, U.S. Attorney General Eric Holder told the Senate Judiciary Committee March 6, Bloomberg reported.

Holder told the committee that criminal charges against large banks can threaten their existence, which then threatens the nation’s economic stability.

Several U.S. lawmakers, including Sens. Elizabeth Warren, D-Mass.; Charles Grassley, R-Iowa; and Sherrod Brown, D-Ohio, have expressed ongoing concern that big banks are not being held accountable for their role in the financial crisis, Bloomberg reported.

Grassley and Brown previously have asked the U.S. Department of Justice to respond to accusations that it has failed to prosecute banks because some are “too big to jail.” DOJ said that federal prosecutors have followed internal rules, which include taking into account the economic impact of their decisions should they pursue a criminal case.

Brian Gardner, senior vice president for Washington research at financial services firm Keefe, Bruvette & Woods, told Bloomberg that Holder’s comments to the Judiciary Committee “will further stoke the debate over breaking up the large banks.”

In his testimony, Holder told lawmakers that he believed the best deterrent to future wrongdoing on Wall Street is to go after individuals, not corporations. “Prosecute the individuals in the corporation who are responsible for those decisions,” he said, Bloomberg reported.