German billionaire Adolf Merckle, one of the 100 richest people in the world, has killed himself by jumping in front of a train—emotionally "broken" over a bad bet on Volkswagen last year.

Merckle's business interests came out on the wrong side of last year's short squeeze of Volkswagen. Rival Porsche silently cornered the market on Volkswagen shares, and when they revealed the extent of their stake, the price of Volkswagen stock shot up to levels that made it briefly the world's most valuable corporation. Many hedge funds who had bet against Volkswagen shares lost huge amounts of money, while Porsche made billions in profit.

Merckle, whose personal wealth was estimated at more than $9 billion. reportedly lost a billion alone on the Volkswagen stock, which shocked his employees. The loss led to margin calls from other creditors and threatened to unravel his entire private business empire. But otherwise he had a rather demure reputation:

Merckle personifies the wealthy but discreet German entrepreneurs who run their businesses in ways that were "worthy of the 19th century," according to a press report.

Born in eastern Dresden in 1934 and father of four children, Merckle inherited in the late 1960s a small pharmaceutical company from his father that employed 80 people.

Little by little, he built an empire, with sales of around 35 billion euros and more than 100,000 workers.

And now he's dead.