Employees of two local public relations firms are also among the eight people being investigated by Shanghai police.
The probe into the 21st Century Business Herald newspaper is one of the biggest into the local media since President Xi Jinping launched a sweeping crackdown on corruption when he took over the ruling Communist Party in late 2012.
Experts have long said corruption was rife within Chinese media, with poorly paid journalists often susceptible to bribery.
The newspaper is widely considered an influential business daily but it is not run by the government.
The editor-in-chief of its website and other staff are accused of colluding with two PR firms.