Banc of America Securities and Merrill Lynch have risen to the top of the merger and acquisition rankings for US health care deals as the two banks join Bear Stearns in advising Boston Scientific on its $25bn (€21.2bn) counter bid for rival Guidant.

Merrill and Banc of America are providing financing for the transaction. Joseph Kohls, Michael McIvor and Barry Watters are the managing directors at Banc of America leading the deal.