Simpson Thacher & Bartlett has scored the highly coveted lead role on JP Morgan Chase’s $58bn (£31.6bn) take-over of Bank One, creating the second largest bank in the US.

The deal, a further sign of renewed confidence in the US M&A market, sees the banks combine on a stock-for-stock merger in which 1.32 shares in JP Morgan for every share in Bank One. The new entity will operate under the JP Morgan brand.