The reward is up to $1,600 for information leading to the arrest and conviction of the people responsible for the bomb scare on Black Friday.
The Mining Journal announced a $500 reward Saturday.
Its publisher, Jim Reevs, said he was furious about the incident and its effect on local businesses.
Reevs also challenged other area businesses to add to the reward fund, and some of them have.
The reward amount has grown to $,1600 from community donations, including from Wal-Mart, Econo Foods, Holiday Inn and the Westwood Mall.
Anyone with information related to the bomb threats is asked to call the Marquette Police at 228-0400.