A half-dozen firms are working on a large specialty chemical company stock-for-stock merger between the Swiss company Clariant and Huntsman Corp. based in The Woodlands, a planned community north of Houston.

Huntsman is represented by Kirkland & Ellis, Vinson & Elkins and Swiss firm Bar & Karrer Ltd. Clariant turned to Cleary Gottlieb Steen & Hamilton and Swiss firm Homburger.