El superpeso is back. For the first time since 2002, a dollar buys less than 10 Mexican pesos.

The last time it was this strong, earning the superpeso nickname, it caused alarm for exporters, who thought it wildly overvalued. But once inflation in the two countries is taken into account, it is more overvalued now, even compared with an inflated 2002 base. Prices have risen more in Mexico. To maintain purchasing power parity, the dollar should have risen by 18.7 per cent since 2002.