Surrey operator Buses Excetera has suddenly closed.
The Merstham business operated six school routes and two commercial bus routes. Schools were left struggling to get pupils home after it ceased trading with no warning.
It has given no notice of closure on its website, and was not answering the phone when routeone called for comment.
Its commercial service 28 from Guildford to Woking is now being operated by Falcon Buses, while its school services have been picked up by Safeguard Coaches, Cardinal Buses and Go-Ahead London Central.
The operator’s county council contracts were transferred to other providers last year.
The company’s current director is Daniela Gianina Ciortan, who is based in West Bromwich.