North Korea presents a big challenge for fund managers: how to invest in the world's longest surviving Communist state? To many people, it is a bellicose, isolated Stalinist basket case. To a handful of investors, it is one of the purest, and perhaps most challenging, frontier markets on the planet.

There is, of course, no stock market, and the country issues no sovereign bonds after reneging on its debt more than 25 years ago. Even people who successfully did business with the Eastern Bloc in the years before and during glasnost and perestroika seem daunted.