Puma Energy said it had acquired the Milford Haven facility along with three English inland terminals at Westerleigh, Theale and Bedworth.
Murco retained about 60 refinery staff at Milford Haven out of 400 when another deal to sell the plant failed.
Puma Energy said it will convert the site into a storage facility.
The company, which is is part-owned by Swiss-based commodity trading giant Trafigura and Angola's national oil company, said there are around 100 jobs at Milford Haven and 40 at the other three depots which will be kept.
A Welsh government spokesman said: "This is good news for all the staff who will remain and for Pembrokeshire and south Wales as a whole.
"However, over 400 employees and contractors have lost their jobs, plus more in the wider supply chain."
Pembrokeshire's Murco oil refinery site has been bought four months after a separate sale collapsed, leading to hundreds of job losses.