Members of the Congressional Progressive Caucus are requesting that the Justice Department investigate possible antitrust violations by major banks  that recently tacked on monthly fees to debit cards.

Reps. Peter Welch (D-Vt.), John Conyers (D-Mich.), Keith Ellison (D-Minn.), Mike Honda (D-Calif.) and Raul Grijalva (D-Ariz.) announced Thursday that they asked Attorney General Eric Holder to launch an inquiry into possible collusion by Bank of America, Chase and Wells Fargo.

Bank of America announced last month that it would charge $5 per month to customers who use their debit cards for purchases.

Chase and Wells Fargo have also begun testing $3 monthly debit card fees for similar reasons in certain markets.

The congressmen acknowledged that they had no hard evidence of a cartel-like arrangement, but said that the timing of each bank’s fee policy, and statements made by banks and their trade associations warrant an investigation into collusive behavior.

“You don’t have a competitive marketplace,” Welch said at a news conference, according to the AP ^[1].

In their appeal to the Attorney General, the legislators refer to an e-mail sent by the Texas Bankers Association. The letter advised members how to reshape business models in the wake of a failed bill that sought to delay a cap on debit card fees. The cap was imposed by Congress and the Federal Reserve.

The e-mail said that “the industry must regroup and each and every one of you must decide how you are going to pay for the use of debit cards. It may be through a monthly fee.”

Bank of America will start charging the fee in early 2012, and Chase and Wells Fargo have not yet revealed when they expect to make a final decision on debit card fee policy.