Cain Brothers | 9,998 followers on LinkedIn. Cain Brothers, a division of KeyBanc Capital Markets, is a pre-eminent healthcare investment bank | Cain Brothers, a division of KeyBanc Capital Markets, is a pre-eminent healthcare investment bank. We deliver innovative solutions and fresh ideas to our clients in mergers & acquisitions, debt and equity financing, and strategic and financial advisory from our offices across the country. Our deep knowledge of the industry is matched with the knowhow needed to efficiently execute the most complex transactions of all sizes.