BASF has decided to exercise the put option in its 2011 joint venture agreement with Ineos and sell its 50 % stake in Frankfurt, Germany-based styrenics producer Styrolution to the Swiss-based partner for €1.1 billion.

The sale is expected to close at the latest in the fourth quarter of this year following regulatory approval. In future, Styrolution will be a subsidiary of Ineos Holdings; in the interim it will continue to operate independently.

The German group long ago made clear its intention to exit the styrenics business. Before forming the joint venture with Ineos, it had sought unsuccessfully to sell its assets.

BASF's option to sell to Ineos comes due in October this year. At the group's annual results press conference at the end of February, however, CEO Kurt Bock had left the exit date open, saying the business "has developed nicely and targeted synergies have been achieved. We are happy shareholders and don't have to do anything."

World's largest styrenics player, Styrolution has fulfilled its promise as a globally competitive business that competes effectively with large-scale producers from Asia and the Middle East, said Ineos chairman Jim Ratcliffe.

The company with annual sales of €5.8 billion and EBITDA of €442 million in 2013 produces PS, ABS and SAN at locations in Europe, North America and Asia. It is also one of the leading producers of styrene monomer.