The co-founder and current CEO of US wholesaler Costco is to step down from the top job.

Jim Sinegal, who set up the business in 1983, plans to quit as CEO at the end of the year.

President and COO Craig Jelinek will replace Sinegal on 1 January next year. Costco created an office of the president in February through which Sinegal and Jelinek have “worked hand in hand” on company matters, alongside chairman Jeff Brotman.

Jelinek joined Costco in 1984 as a warehouse manager and Sinegal said he had “total confidence” in his successor.

“Costco has a very strong culture and a deep bench of management talent,” Sinegal said. “I have total confidence in Craig’s ability to handle his new responsibilities and feel we are fortunate as a company to have an executive of his calibre to succeed me as chief executive of Costco.”

Sinegal will work as an advisor to Costco until January 2013 and will also continue to serve on the company’s board.

The news of Sinegal’s departure was made yesterday (31 August) as Costco reported its annual sales. Net sales for the year to 28 August were US$87bn, an increase of 14% on a year earlier.

Comparable-store sales climbed 10% thanks to a 7% increase in the US and a 16% jump in Costco’s international markets.

Excluding fuel and the effect of exchange rates, Costco’s comparable-store sales were up 6%.