Tengelmann chief Karl-Erivan Haub missing in Swiss Alps

Karl-Erivan Haub has been head of the Tengelmann retail empire since 2000

Rescue teams are searching for one of Germany's richest men, who has gone missing while skiing in the Swiss Alps.

Karl-Erivan Haub, heir to the Tengelmann supermarket chain, did not return from an off-piste skiing expedition near the Matterhorn on Saturday.

A Tengelmann spokeswoman confirmed on Wednesday that a "full-speed" search for Mr Haub had begun.

The 58-year-old billionaire has been in charge of the firm since 2000.

It owns various supermarket brands in Germany and Central Europe.

The Matterhorn is on the Swiss-Italian border

In a letter published in the German newspaper Handelsblatt, the supermarket boss' brother, Christian Haub, said he was an experienced skiier and mountaineer.

He said he was still hopeful his brother would be found, but that the Haub family - one of Germany's wealthiest - was "prepared" for bad news.

If Mr Haub could not be located, "the business will continue to run smoothly and orderly", he added.