The European Commission has blocked — on anti-competition grounds — the merger of South Korea’s Hyundai Heavy Industries and compatriot Daewoo Shipbuilding & Marine Engineering (DSME), which would have created the world’s largest marine and offshore contractor.

The Commission’s decision effectively brings to a halt Hyundai Heavy Industries’ planned $1.8 billion acquisition of DSME with the intent of merging it into parent Korea Shipbuilding & Offshore Engineering (KSOE).

Hyundai Heavy Industries, which this year celebrates its 50th anniversary, would then have held a majority stake in DSME.