US trio Simpson Thacher & Bartlett, Sidley Austin and Sullivan & Cromwell have bagged plum roles on the latest multibillion-dollar buy-out as credit card processing group First Data is taken private for $29bn (£15bn).

Simpson Thacher is advising private equity giant Kohlberg Kravis Roberts & Co (KKR) on its bid for the group, which is expected to be completed by the end of the third quarter. New York corporate partners Gary Horowitz, Sean Rodgers and James Cross are leading the Simpson Thacher team.

Meanwhile, Sidley acted for the target, while Sullivan advised the company's independent directors.

Last year, a string of large leveraged buy-outs (LBOs) drove the US M&A market to a record year, with 2007 also seeing a number of big-ticket transactions. Headline deals include the $45bn (£23bn) LBO of utilities giant TXU by KKR and Texas Pacific Group – potentially the biggest private equity deal ever.

Simpson Thacher advised KKR on that deal, with Manhattan rival Cleary Gottlieb Steen & Hamilton acting for Texas Pacific. Sullivan and Cravath Swaine & Moore acted for the target.