It has been eight months since national oil firm Petróleos Mexicanos applied for a permit to buy U.S. light oil in a swap for Mexico’s heavier blend, but the company says it is confident it will get U.S. Commerce Department approval and isn’t looking to alternative sellers, a senior Pemex official said. “The signs are positive,” said José Manuel Carrera, head of Pemex’s commercial arm PMI. “We continue to be respectful, but always very insistent that this happens as soon as possible,” he said in an interview last week. The U.S. maintains a ban on crude-oil exports dating back to the 1970s, but swaps are allowed when exports are balanced by additional imports. And while both the U.S. and Canada allow swaps, the subject is politically sensitive given how dependent the U.S. has been on massive oil imports in the recent past. There is little precedent to measure […]