Construction company Dawnus – which employs 700 people – has gone into administration, it has been confirmed.
Administrators Grant Thornton said the Swansea-based firm had gone bust on Friday after work was halted on several UK projects.
Contractors were called to a meeting on Thursday where they were told Dawnus had been placed into administration.
Administrator Alistair Wardell said the group faced a “wide variety of challenges”.
He added: “Whilst the financial difficulties of the group were not a consequence of Brexit, there is no doubt that Brexit uncertainty impacted the ability to rescue the business.”
The group is currently working on 44 construction sites across the UK and work on Swansea’s £12m Kingsway redevelopment was stopped on Wednesday amid the uncertainty.
Three school projects in Powys and a road in Fishguard, Pembrokeshire, have also been affected.
The boss of one sub-contracting firm, who did not want to be named, said after the meeting: “We got wind that there were problems a few weeks ago and decided to remove some equipment on site as a precautionary measure.
“We are still out of pocket – but thankfully not a significant amount.
“I think we might have got off lightly compared with what I’ve heard about other firms.”
What is Dawnus?
Dawnus has its headquarters in Swansea but runs construction projects across the UK and overseas.
The most recent company accounts show the company had a turnover of £170m in 2017, but posted a pre-tax loss of £1.35m.
Last September, the company said it employed 700 people.
As well as domestic construction, it previously operated in west Africa and worked on projects during the Ebola crisis.
In August, during a UK trade mission to South Africa attended by Prime Minister Theresa May, Dawnus was unveiled as part of a consortium targeting overseas aid contracts.
The company told BBC Wales in September it felt optimistic about life after Brexit because of the opportunities for overseas work.