Marc Rich, commodity trader extraordinaire, once gave this advice to an employee: "As a trader you often walk on the blade. Be careful and don't step off." Glencore, the world's biggest commodity trading company, which Rich founded, now seems to be falling off the edge, its business model in question.
On Monday, Glencore's shares were down about 30 percent. Apparently, Glencore's executives themselves didn't know the reason for the freefall, judging by this tweet from Gianclaudio Torlizzi, founder of the consulting and market intelligence company T-Commodity: