Wednesday is D-Day for Mexico’s key energy reform. For nearly 80 years, the oil industry has been concentrated in the hands of Petróleos Mexicanos, or Pemex, the state oil company. But with output in decline for a decade, the government is betting on private investors to turn things round and put the country’s sluggish economy on the path to sustained growth. Mexico has a long tradition as an oil producer — its first well was drilled in 1869, though commercial production did not start until 1901. UK and US companies dominated early production. But Mexico nationalised the industry in 1938 after serious labour disputes, elevating oil to the status of a national treasure with the expropriation anniversary celebrated every year, even by schoolchildren.