NEW YORK (TheStreet) -- Shares of Whole Foods Market  (WFM)  were higher in mid-afternoon trading on Thursday after reporting an earnings beat for the 2016 fourth quarter after Wednesday's market close. 

The specialty grocer announced that it will eliminate the co-CEO structure starting December 31. Whole Foods co-founder John Mackey will be the sole CEO, while Walter Robb will remain on the board of directors and as a senior adviser to the company. 

Based on these results, "I'm not as aggressive on Whole Foods," Douglas C. Lane & Associates' co-managing partner Sarat Sethi said on CNBC's "Halftime Report" on Thursday afternoon.

"I think you've got time to wait here. It might be better to buy it at a cheaper price," he added. 

Although margins improved for the company, same-store sales did not improve, he noted. Same-store sales were down by 2.6% for the quarter.

"What's the deal with the management change there?" O'Shares ETF's Chairman and special guest on the show Kevin O'Leary asked. Anytime a CEO or co-CEO gets "whacked" or leaves for health reasons or other reasons, "bad things happen," he claimed. 

The co-CEO structure didn't work because it's hard for two people to make a decision on where the company should go, Sethi said in response. 

Going forward, Whole Foods needs to figure out how to improve its margins, he said. "They've got the idea now that they can't grow. They need to figure out how to actually grow margins, and how to be the right place for the right person - not just be it for everybody. And that's the issue that I think this CEO is going to have to deal with."

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