Amazon's new strategy is to offer its Prime members free one-day shipping on items priced at as little as $1. Harvard Business School Historian Nancy Koehn joined Boston Public Radio Thursday to explain Amazon's intentions and why it will hurt its competitors.

"It's all about growth and taking on rivals," Koehn said. "In this case, the rivals besides CVS, Walmart and Target are Dollar General and Dollar Tree, since Amazon is going after a segment of customers that are not in the wealthy upper middle class."

Amazon will not directly make money with this tactic, but it will expand its reach and customer base, Koehn said.

"They're not going to make an money on this or get any environmental points for sustainability," she said. "This is about growth more than anything else."

Koehn is an historian at the Harvard Business School where she holds the James E. Robison chair of Business Administration. Her latest book is "Forged in Crisis: The Power of Courageous Leadership in Turbulent Times."