Car giant Ford has announced a voluntary redundancy programme at its Bridgend engine plant.
The company said a voluntary separation programme would affect hourly and salaried employees.
The move, which Ford said was part of its ongoing actions to create a "sustainably profitable business" in Europe, will affect between 350 and 400 jobs.
It is nearly two years since fears of 1,160 job losses at the plant by 2021 emerged in a worse case scenario.
A Ford spokesman said: "The programme follows discussion with the union on matching the plant's labour requirements to the projected production volume expectations in the near term."
Unions said they were told in January that 990 jobs would be cut in Bridgend by 2020 and pledged to fight compulsory redundancies.
Workers were told officially on Friday that they have three weeks to apply and those selected for redundancy will leave later this year.
The American-owned company announced plans last month for a major shake-up of its operations in the UK and mainland Europe.
Bridgend makes engines for Jaguar Land Rover (JLR) but that contract finishes at the end of 2019, at around the same time the plant will stop making the Ford Ecoboost engine
The factory, which employs about 1,700 workers, won the investment for Ford's latest petrol engine - the Dragon - but that will only employ around 500.
If plans go ahead, the 990 jobs to be lost at Bridgend - almost half of the site's workforce - will go in two phases by 2021, as part of 1,150 losses across the UK.