Jacques Moretti and his French wife Jessica, who own the bar together, had been placed under criminal investigation by Swiss prosecutors.
They are both suspected of manslaughter by negligence, bodily harm by negligence and arson by negligence, the prosecutors’ office in Valais said.
The prosecutors have said they believe the fire started when people celebrating the New Year raised champagne bottles with sparklers attached, setting light to sound-insulating foam on the ceiling of the basement bar.
On Friday, Switzerland staged a minute of silence on a national day of mourning for the victims of the fire.
Church bells then rang across the country for five minutes.
Trains and trams came to a halt and Zurich airport briefly paused operations.
At a local commemoration staged in Crans-Montana, there was a standing ovation for firefighters.
