One day in 2002, Jim Leitner, a hedge-fund manager, read in The Economist that average beer consumption in Nigeria dropped from 34 litres to just three litres and then rebounded to four litres. He did some more research and bought Guinness of Nigeria which went up a few hundred per cent over the next three years. Marko Dimitrijevic, of Everest Capital, is all over the emerging markets. Along...