Cadbury-parent Mondelez International is exploring the acquisition of chocolate maker Hershey, Bloomberg News reported Monday, citing people familiar with the matter.

Mondelez has made a preliminary approach about a possible combination, Bloomberg reported.

Mondelez had a market capitalization of roughly $84 billion, while Hershey was valued at $35 billion as of Friday close.

Shares of Hershey rose 17%, while those of Mondelez were down about 4%.

Spokespeople for Mondelez and Hershey did not immediately respond to requests for comment.