The company boss, 64, came face to face with his alleged abductors as the trial started.
The trial is being held in a secure courtroom, in which the public gallery is separated from the rest of the court by a glass wall.
The five men, all in their twenties and thirties, appeared in court in jeans and hooded tops. They all deny charges of kidnapping and attempted murder.
The company director was snatched from his home in the Hisingen area of Gothenburg in April. He was assaulted and bundled into the trunk of his own car. He was later found with life-threatening injuries and spent a long period in hospital, suffering from a fractured skull, serious eye injuries, missing teeth and broken bones in his hands.
Prosecutor Thomas Eliasson outlined the evidence against the men on Wednesday morning. He said they could be linked to the crime through records from their ATM cards and through the mobile phone calls between them. He also pointed to evidence gleaned from the victim’s car and a car belonging to one of the alleged kidnappers.