One of the accused was the former employee of the businessman, police said.
The incident occurred on March 16 when two of the accused allegedly trailed the trader's car in western suburbs and forced him to stop on highway, police said.
They forcefully entered the car of the businessman, whose name has been withheld by police, and bound and gagged him, before driving towards Mira Road in Western Mumbai.
However, the businessman, who was made to sit on the back seat of the car, jumped out of the vehicle when it slowed down at a turning and fled.
More From This Section
"Eight years ago, Mukesh was working in the complainant's diamond polishing factory," said senior inspector Unit 11, Crime Branch, Chimaji Adhav.
According to police, Mukesh had started his own business some years back but incurred heavy losses.
He came in contact with Pandey, a history-sheeter, a few months back and the duo hatched a conspiracy to abduct the businessman for hefty ransom.
Morbiya, also a history-sheeter, and Parte were arrested for abetment to crime, police said, adding two more persons wanted in connection with the case are on the run.