The partners, whose sector has suffered as oil producers have curbed spending, said the two sets of shareholders will receive stock in a new company, TechnipFMC, at a ratio of one Technip shares for two for investors in the French company and 1:1 for owners of Houston-based FMC. The resultant ownership split will be 50:50, according to a memorandum of understanding the two companies signed.

The companies said the combo would have had revenue of $20 billion last year and Ebitda of $2.4 billion. They expect the union to release at least $400 million in pretax cost savings in 2019.

FMC will install its president and chief operating officer, Doug Pferdehirt, as CEO of TechnipFMC, and Technip CEO Thierry Pilenko will be executive chairman.

"We have complementary skills, technologies and capabilities which our customers can access on an integrated basis or separately as they prefer," said Pilenko in a statement.

Technip shares closed at €46.38 in Paris on Wednesday, translating into a market value of €5.5 billion ($6.2 billion). FMC closed at $28.65, valuing its equity at just under $6.5 billion. Its stock has fallen about 30% in the past year, while Technip is down 20%.