The new Clariant will have annual sales of around 18 billion Swiss francs ($13.2 billion) if shareholders and regulators bless the accord, for which final agreement is expected next month, the partners said in a joint statement.

Clariant shares opened 96 francs higher on the Zurich bourse at 845, while Ciba advanced 33 francs to 160 on the news.

Clariant shareholders will get about 54 per cent and Ciba shareholders 46 per cent of the registered shares of the new company, which will be called Clariant but will maintain Ciba's butterfly logo.

Clariant chairman Rolf Schweizer will be chairman and president, while Ciba chairman Rolf Meyer will be chief executive and vice-chairman.