The panel reviewed the 27 mines in the world's No. 2 nickel ore supplier that former Environment and Natural Resources Secretary Regina Lopez ordered closed or suspended last year.
Sumitomo’s move comes as Japanese trading companies have been grabbing assets and increasing their stakes on a few of them thanks higher commodities prices, which have boosted their profits.
The company's withdrawal means all eyes are now on Fortescue, which still has a 19.9%-stake in Atlas and has not yet disclosed whether it plans to launch a rival bid or sell its holding into Hancock’s offer.
So far, Trump has taken little action beyond tariffs of 25 percent on steel and 10 percent on aluminum on imports from China, the European Union and other countries.
Global demand for nickel is increasing by 7.3 percent in 2018 from last year to 2.298 million tonnes, while supply rises 6.8 percent to 2.210 m tonnes,