Everybody in the news business knows you can't tell the same story in the same way every year, and if you're going to try, you need to disguise it with a new twist. So it is with Forbes' annual billionaires list. How do you keep it fresh and oh-so-exciting in a year of falling fortunes?

Try putting in a drug dealer. If you've been following the news at all, there's a good chance by now that you know that would be Joaquin Guzmán Loera, czar-is that the right word?-of Mexico's Sinaloa cocaine cartel. Forbes' much-quoted 2009 list puts his net worth at $1 billion. You can almost see Steve Forbes' deep-set little eyes twinkling. The billionaire drug dealer! There hasn't been an idea this marketable attached to Forbes since the flat tax!

In just a few days, the billion-dollar number has been repeated so many times that's it already certifiably truthy—the au courant term for what journalists used to call "too good to check." Which is exactly what makes it worth checking.

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Over the past days, TBM has made an effort to get to the bottom of Forbes' number. The magazine does give you some back of the envelope calculations. According to Forbes' Guzman blurb, "Mexican and Colombian drug traffickers brought in $18 billion to $39 billion in wholesale cocaine shipments to the US last year. Guzman's organization took in, by Forbes' estimate, 20 percent of that-which makes for $3.6 billion to $7.8 billion in revenues. That's a good start. But then Forbes punts saying simply that's "enough for him to have pocketed $1 billion over the course of his career and earn a spot on the billionaire's list for the first time."

Well, maybe. With assassinations going at several thousand dollars a pop, and the costs of security and the like, you'd think that Guzman's expenses are substantial-even considering that his earnings are tax free. And however much money Guzman has managed to pocket, we can assume that a fair amount has been spent. Knowing you might die any day of the week doesn't exactly encourage thrifty habits. Our first thought was to turn to Forbes for a little bit more explanation. We weren't expecting a dollar-by-dollar accounting. But it seemed like if you're going to put a number out there, you might be able to divulge at least a general sense of how to value an international drug trafficking business. No such luck. In fact, the response we got to our query from Forbes spokeswoman Monie Begley is short enough that we can reprint it in full:

"Thanks for your inquiry. The Forbes methodology is proprietary." That's it. Not much to go on, is it?

Yet if you really want to, you can come up with an estimate of the value of Guzmán's business. The best place to start is probably at the source—by counting up how much cocaine goes through Mexico.

The latest numbers on cocaine production in the Andes show a marked increase in the last few years, with total production up to 994 tons. The biggest cocaine bust in history was a seizure of 23 tons in Mexico City at the end of 2007-an enormous haul for a single shipment that serves as a reality check and makes the overall number of close to 1,000 tons fairly plausible.

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The biggest portion of that-55 percent, by the estimate of Colombian authorities (you can get this number and much more in this 2008 study)-goes through Mexico, with a much smaller part going through Venezuela and a still smaller part traveling from other parts of Latin America to Europe through West Africa, a growing but still small trafficking route. So we can conservatively estimate the portion going through Mexico's cocaine cartels at 550 tons. One estimate of the wholesale price of cocaine in Mexico puts it at $8,000 per kilogram, or about $7,275,000 per ton. That would put the total wholesale price of the cocaine shipped by the cartels at about $4 billion.

That's a whole lot less than the $18 billion to $39 billion that US authorities claim, and that Forbes uses for its numbers. Why do we think the Forbes numbers are high? Well, the high estimate of $39 billion would mean a wholesale price of close to $44,000 per kilo—a number much higher than almost every other estimate out there, and approaching the street level retail price of cocaine. And that assumes all of South America's drug production (for which US drug authority estimates are actually a bit lower than the UN's) went to the US.