The head of the company that operated the sunken South Korean ferry and four managers have appeared at a preliminary court hearing.
Chonghaejin Marine's chief Kim Han-sik, 73, and four employees are charged with negligence over claims that the company routinely overloaded the Sewol.
A separate trial of the captain and 14 other crew members began last week. They face various charges related to their failure to help passengers, the BBC reports.
At least 292 people, mostly school students, died in the 16 April tragedy.
The disaster has caused an outpouring of public anger in South Korea and there have been calls for severe punishment for the crew.
Yoo Byung-eun, who is thought to control the ferry company through various holding firms, remains on the run. He has been the target of a nationwide manhunt since he refused to respond to an official summons in May.
Diving teams are still trying to find 12 people still regarded as missing from the ferry. The latest underwater search failed to find new bodies from the sunken vessel.