Julie Hoff

Senior director of HR strategy, planning and communications, Express Scripts Holding Co., St. Louis

PHARMACY BENEFIT MANAGER Express Scripts Holding Co.'s acquisition of Medco Health Solutions Inc. stirred up controversy among lawmakers and consumer groups and marked a difficult time for the company, but for Julie Hoff it was the opportunity of a lifetime.

The $29 billion deal finalized earlier this year that brought together Express Scripts and Medco was a complicated merger of distinct cultures and 33,000 employees from across the country. It doubled the size of Express Scripts, which is now the largest PBM in the country.

Hoff, 36, was responsible for developing and executing human resources strategy during the acquisition.

"It's so massive in size and complexity that it could become overwhelming," says Hoff, who started at Express Scripts in 2003 as an entry-level HR generalist and now is senior director of HR strategy, planning and communications. …