NEW YORK - Panera Bread said founder Ron Shaich is stepping down as CEO and the company will buy Au Bon Pain -- bringing together two chains Shaich helped build.

The companies did not disclose on Wednesday how much Panera was paying for Au Bon Pain. Shaich will be replaced as CEO Jan. 1 by Blaine Hurst, who oversees Panera's restaurants. Shaich will stay on as Panera's chairman and will continue to work on the chain's strategy and future acquisitions.

"This is the right time for me to step down as CEO while still staying involved in the business," said Shaich, in a statement.

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It has been a year of change for Panera: In July, it was bought and taken private for more than $7 billion by JAB Holding, a European company that has controlling interests in Krispy Kreme, Peet's Coffee and other chains and coffee brands.

Panera said it's buying Boston-based Au Bon Pain to boost its presence in airports, hospitals and colleges, where many of its 300 locations are. The deal brings the two chains back together again: They were part of the same came company in the 1990s, until Au Bon Pain was sold in 1999 to a private equity firm and Panera became the focus.

Boston-based Au Bon Pain, operates more than 300 locations, and St. Louis-based Panera has more than 2,000 restaurants.