Swansea-based Diamond Coach Holidays has ceased trading as it seeks to bring in administrators.
BBC Wales has reported the operator, the largest in the coaching holidays sector in Wales, was looking to appoint administrators today.
The firm operates coaching holidays throughout the UK and Europe having been established in 1954 and has 80,000 customers annually.
The BBC reported a sign outside its Cardiff premises is advising visitors that the firm, which employs around 70 people, has ceased trading.
Diamond has two shops, one in Swansea and one in Cardiff, and is said to have recently invested £5 million in 20 new vehicles.