Arla Foods in Denmark, one of the biggest dairy co-operatives in Europe, is about to get bigger.
Its board has approved mergers with Milk Link of Britain and Milch Union Hocheifel, a German company.
The merger with Milk Link will create the largest dairy operator in the British market, processing more than three billion litres of milk per year.
Arla is number eight on Rabobank's top 20 list.
Fonterra had a joint venture with Arla in Britain, marketing butter and other products, but sold it to Arla in 2009.
But it still licenses the Anchor brand to Arla and supplies New Zealand butter.