In a move that surprised some but others had anticipated, the transatlantic multi-billion dollar fusion of the two specialty chemicals producers Clariant of Switzerland and Huntsman of the US has been called off.

The deal, which would have had an enterprise value of $20 billion, ran aground on the opposition of an activist investor five months after it was announced and shortly before it was due to be approved by shareholders in November. Targeted closing date was the end of 2017.

In a statement, Clariant CEO Harriolf Kottman and Huntsman CEO Peter Huntsman said they remain convinced that the merger is in the “long term best interests of all of our interests of all of shareholders.”  However, due to the “continued accumulation of shares” by activist investor White Tale Holdings and its opposition to the transaction – which allegedly is now supported by other shareholders – they believe that there is “simply too much uncertainty.”

Clariant reportedly feared it would have had difficulty securing the two-thirds majority required to approve the transaction under Swiss law, and thus would have faced break-up fees. With the fusion prematurely off, no break-up fees will have to be paid.

While the Swiss player did not comment further, Peter Huntsman insisted that a merger was not the only option for the US chemical producer to create “real and lasting value.” He said the family-run company will continue to focus on organic growth and “appropriate” bolt-on acquisitions, strong annual free cash flow and deleveraging, while reaching investment grade metrics in 2018, strengthening the balance sheet and monetizing the remaining shares in coatings spinoff Venator.

In late September, White Tale, which had been persistently talking the deal down, said it had boosted its stake in Clariant to 15.1% from 51.3% in early July, when it first revealed its goal to drive a wedge between the prospective partners. On Oct. 26, the funds triumphed that they had acquired 20%.  The acquisition vehicle for US hedge funds Corvex and 40 North believes a direct sale of Clariant or some of its parts would yield a higher return than combining with Huntsman.

The investor has repeatedly urged the Swiss company’s management to divest its carved-out Plastics & Coatings unit, said to account for 40% of sales. As part of a transaction update in August, Kottmann stressed again that Clariant might be willing to part with the business, but indicated it would be on the company’s own terms.