Carrefour's two major investors are reportedly mulling whether to replace the retailer's chairman and CEO Lars Olofsson.

Groupe Arnault, the holding company of French billionaire Bernard Arnault, and US private-equity firm Colony Capital, plan to give Olofsson until the end of the year to turn around Carrefour's business in France, Bloomberg reported today (21 November).

The report, which cited sources that wanted to remain anonymous, adds to the uncertainty over the future of Olofsson, who joined Carrefour in 2009.

The world's second-largest retailer has issued a number of profit warnings this year. Its latest warning, issued last month, forecast that its annual operating income could fall by 15-20% in 2011.

Last month, another Carrefour shareholder, US investment fund Knight Vinke Asset Management, urged the retailer to appoint an independent chairman and suggested it could have two CEOs.

Groupe Arnault, Colony Capital and Carrefour could not be reached for immediate comment.