German billionaire Karl-Erivan Haub goes missing during ski trip in the Swiss Alps

Billionaire and one of the richest men in Germany, Karl-Erivan Haub, has been reported missing after failing to return from a skiing expedition in the Alps on April 7 2018.

Haub, who is the owner and CEO of retail group Tengelmann, last week embarked on an off-piste skiing expedition in the resort of Zermatt near the Swiss-Italian border.

According to Spiegel magazine, a search is underway for the 58-year-old, with Deutsche Welle adding that a spokesperson for Tengelmann said the search was proceeding at "full speed.

" The search has been disrupted by poor visibility and the threat of avalanches, Deutsche Welle said.

Haub was reportedly in Zermatt to train for the Patrouille des Glaciers ski race, an international long distance ski event organized by the Swiss army, scheduled to take place next week.

Haub's brother, Christian described him as "a very experienced alpinist and skier," in a letter sent to staff, and partially published in the newspaper Handelsblatt

"Of course our family is prepared for such a situation," Christian Haub said, adding that "the business will continue to run smoothly and orderly."

According to the Bloomberg Billionaires index, the net worth of missing Haub's father, Erivan Karl who died last month, was in excess of $6 billion (£4.2 billion; €4.9 billion).

That wealth stemmed from Tengelmann, which owns German retailers including hardware chain Obi and textile discounter Kik. The company has stakes in as many as 73 different businesses.