James T. Tierney, Jr. is Chief Investment Officer of Concentrated US Growth. Prior to joining AllianceBernstein in December 2013, he was CIO at W.P. Stewart & Co. Tierney began his career in 1988 in equity research at J.P. Morgan Investment Management, where he analyzed entertainment, healthcare and finance companies. He left J.P. Morgan in 1990 to pursue an MBA and returned in 1992 as a senior analyst covering energy, transportation, media and entertainment. Tierney joined W.P. Stewart in 2000. He holds a BS in finance from Providence College and an MBA from Columbia Business School at Columbia University.

Michael Walker is a Senior Vice President of WPS Advisors, Inc. and an Analyst/Portfolio Manager on the U.S. equity research and portfolio management team. Prior to joining W.P. Stewart in 2009, Mr. Walker was the technology sector analyst on the large cap growth fund at Ark Asset Management. Before joining Ark in 2007, he spent nine years at Donaldson, Lufkin & Jenrette and then at Credit Suisse First Boston as a senior research analyst covering the IT hardware and electronics supply chain sectors. Mr. Walker was the top-ranked analyst in his sector on Institutional Investor magazine's All-America Research Team survey in 2006, after ranking third in 2004 & 2005. Prior to beginning his finance career at DLJ in 1998, he was an IT consultant with Deloitte Consulting. Mr. Walker graduated magna cum laude with a degree in Economics from the Wharton School at the University of Pennsylvania.