A grand jury has charged a Florida man with plotting to set off explosions in Target stores so that he could gain financially from a plunge in the company’s stock price.

An indictment filed Wednesday in federal court in Ocala charges 49-year-old Mark Barnett with five counts of attempted arson, possession of a destructive device and unlawful possession of a weapon.

A criminal complaint says the convicted felon offered a friend $10,000 to place packages of food filled with explosives at Target stores along the East Coast…