In general, senators and their staff members are free to accept meals while they are in the capital.
Representatives and their staff members may accept meals if the cost is less than $50 a meal.
The officials are accused of accepting lavish meals and entertainment.
The officials are suspected of having accepted lavish meals, and then showing favor to the banks that entertained them.
The prosecutors said the officers accepted meals and services and demanded regular payments.
After a long, emotional debate during the spring, the Senate passed legislation that would bar lawmakers from accepting meals, entertainment and trips.
For example, The Times is adamant about its contributors' not accepting free travel or meals.
Under Federal law, members of Congress may accept free travel, lodging and meals when they are on official business - giving a speech, for example.
It made bureaucrats far more careful about accepting meals or entertainment from business executives.
Federal Reserve employees can no longer accept free meals and gifts from banks they regulate.