Port Talbot building firm Jistcourt in administration
BBCA Port Talbot construction company has gone into administration putting about 50 jobs at risk.
Rob Norman, chairman of Jistcourt, said after almost 40 years trading, it had "unfortunately" filed a notice of intention.
The family-run company also has offices in Bristol and the south-west of England.
Mr Norman said: "We will be contacting all creditors in the coming weeks.
"I would like to thank my loyal members of staff, family and friends for supporting us throughout the years."
The company, founded in 1980, specialises in housing association and local authority developments.
The news follows the collapse of Swansea construction firm Dawnus in March, with debts of £50m and the demise of Neath-based Cuddy Group last year.
Neath Port Talbot council leader, Rob Jones, called it "deeply saddening".
"It will be a worrying time for its many employees and suppliers and the council will do whatever we can to support them at this time of uncertainty," he said.
"We are already working to fully understand the implications of the news on the local and regional economy and to help minimise any negative impacts that may arise as a result.
He said the council did not have any contracts in place with the company so ongoing regeneration investments across the county borough would not be directly affected.
Huw Powell of administrators Begbies Traynor said "challenging, loss-making projects" caused cash problems.
"Despite a strong order book, this has left the business with a legacy of debt and no way of rectifying the situation," he said.
"Reluctantly, the directors have taken the difficult step of making 47 of their 66 employees redundant.
"Together with the remaining staff, Jistcourt's directors will be working with clients on remaining live projects to bring them to a workable conclusion."