Under Jack Brennan's leadership, Vanguard became an early adopter of the Net Promoter System. With it, customer loyalty became core to how the investment company operated. Jack pushed employees to ask "Are we doing the best thing for the client?" until the question became second nature to them. The goal was always to keep clients for life and to never take on a client they couldn't keep that long. In this episode of the Net Promoter System Podcast, Jack shares some of the practical lessons he learned from his experience at Vanguard.