The 28-year-old man, a dual German and Russian national identified as Sergei V., had bought options on Borussia Dortmund's stock before the attack, hoping to make a profit, it said in a statement.
The players' bus was heading to their stadium for a Champions League match against AS Monaco on April 11 when three explosions occurred, wounding Spanish defender Marc Bartra and delaying the match by a day.
The suspect is accused of attempted murder, inflicting serious bodily harm and causing an explosion, the prosecutor's office said.
It said he had bought 15,000 put options (defined as 'an option to sell assets at an agreed price on or before a particular date') or contracts, giving him the right to sell Borussia Dortmund's shares at a pre-determined price, on the day of the attack, using a consumer loan he had signed the previous week.
"If the shares of Borussia Dortmund had fallen massively, the profit would have been several times the initial investment," the prosecutor's office said.
Read the full article on eurosport.co.uk: Suspect arrested for Dortmund bus attack 'hoped to profit from shares falling'