Whole Foods announced yesterday that Walter Robb, who has served as co-CEO for the last six years, would no longer serve in that position but will remain as a member of the company’s board of directors. John Mackey, with whom Robb has served as co-CEO, will become the sole CEO. The changes will take effect on December 31, 2016.

The announcement came at the same time the company reported fourth quarter results that included some figures below analyst’s estimates. For example, comparable store sales fell by 2.6% on a 4.2% store traffic decrease as compared to the same time period a year ago. On the positive side, sales met analyst expectations at $3.5 billion, and were up by 1.7% from the previous year.

Net income increased by 57.1% (to $88 million) as compared to the same period last year.

For 2017, Whole Foods is planning for sales growth between 2.5% and 4.5%, and comps from -2% to flat. 30 new stores are planned in 2017, including six relocations and four new 365 stores.

The company also announced that CFO Glenda Flanagan would retire at the end of 2017. Flanagan has been with Whole Foods for nearly 30 years.