Kraft Foods and Mondelez Global have been accused of making more than $5m by manipulating the wheat market. The US Commodity Futures Trading Commission's (CFTC) accusations relate to what it suspects was a false attempt to buy $90m-worth of wheat futures. It also alleges that Kraft engaged in noncompetitive trading.
The CFTC contends that Kraft intended to cause a price drop in the cash wheat market.
Both companies were named because the alleged offence occurred before Kraft split into two entities in 2012.
The US grocery operation is still called Kraft - while its former confectionery brands, including Cadburys, Milka, and Chips Ahoy! now come under the Mondelez International banner.
Heinz and Kraft announced last week that they are to merge into one company - making the world's fifth largest food and beverage firm - it will operate as the The Kraft Heinz Company.
The new entity is expected to generate annual revenues of $28bn.
In February, Cadburys' parent company - Mondelez Ireland - announced that it intends to seek up to 160 redundancies. It also plans to close its gum factory in Tallaght in Dublin with the loss of 62 jobs.
The Rathmore plant, which employs 84 people, has been in operation since 1948 - while the production plant in Coolock opened in 1964 and employs more than 700 people.
