It has been a pretty dismal time for adventurous investors exploring frontier markets. I won’t recount the grim statistics – except to say that you wouldn’t have made much money if you’d listened to my suggestions and bought frontier funds such as Progressive Advance Frontiers, or followed my ill-timed suggestion to snap up investments in Vietnam or Africa.

However, this shouldn’t blind investors to the longer-term opportunities – in particular in Tunisia and Mongolia over the next decade.

First, Mongolia. I’ve been quietly tracking the fortunes of Polo Resources, the mining group, for some time (Investors Chronicle ran a “Buy” tip on it last month). Its big news is a potentially huge deal with Peabody, the US coal miner – the two are planning to put Polo’s coal reserves into a joint venture. It has also received a private equity offer from bidders attracted by the $78m cash on its balance sheet. Whether this will all amount to anything, I don’t know – but it focuses attention on the development potential of Mongolia.

Viktor Broczko at Progressive sums it up: “Some go as far as claiming that it would be the richest country per capita if its mineral wealth (coal, copper, fluorite, gold, iron ore, oil, uranium) was properly exploited. It is the 19th largest country by territory with a population of 3m. Only 22 per cent of its land has been properly surveyed. The potential is huge.” Quite.

In spite of some political trouble, it’s still a relatively safe place to do business with a democratic system, freedom of speech, 80 per cent arable land of which only 1 per cent is used, and access to a hungry country next door called China.

I’m not going to overlook the fact that the education system is poor, the weather is harsh and that nasty Russian and Chinese types might stand in the way of any long-term gain for outside investors. These are all big risks.

But if just a few of the billion-dollar mineral projects in Mongolia – and there are more than 15 – hit the jackpot, then the domestic stock market could shoot up in value. As Viktor says: “I think it is not impossible that Mongolia will follow Kazakhstan’s example, where no major power or superpower has dominance over the country’s resources.” The only problem is that, apart from Polo, there are few ways to access this story. To my knowledge, there’s only one other specialist fund, run by a Singaporean team with Jim Rogers and Marc Faber – aka Dr Doom – as advisers.

Second, Tunisia, which is a more developed place, with lovely beaches, nice well-educated people, and a government that’s… how to put this… fairly decent as long as you don’t disagree with it too strongly.

In investment terms, it first cropped up on my radar as a holiday home location. Everyone has been raving about Morocco or Cape Verde but Tunisia has quietly been growing in popularity, thanks to specialist outfits such as GEM Estates. Big, new high-spec resorts are emerging, aided by Middle Eastern money, and the local property market looks pretty solid with 80 per cent owner occupation.

Tunisia cropped up again when I was investigating the Global Middle East and North Africa (MENA) Financial Assets fund (ticker symbol GMFA) for my bombed-out Dr Strangelove portfolio. The fund has crashed in spectacular fashion but one of its private equity holdings is a large Tunisian stockbroking firm, which appears to be doing very well, largely powered by local demand (see my online Adventurous Diary, details below). Last year, for example, the Tunisian stock market was among the best performing in the world – it ended the year up 3 per cent in US dollar terms while most markets collapsed.

So far in 2009, the Tunisian market – boasting about 40 actively-traded stocks worth $6bn – is up 6 per cent in local currency terms and down 3 per cent in US dollars. As Slim Feriani, fund manager at Progressive and himself a British Tunisian, points out: “This makes it a star performer within a global context.”

So his Advance Frontiers fund has been upping its investment in the country to 4.5 per cent. He says: “The Tunisian economy remains largely insulated from the ongoing global recession. While the export and tourism sectors are getting badly hit by the severe economic slowdown in its major trading partner (Europe), the Tunisian economy is likely to continue to benefit from its growing investments in infrastructure and its domestic engine.”

Luca Del Conte, another Tunisian expert at MediCapital, the African investment bank, also points to the extensive Algerian and Libyan interests of big Tunisian companies and the relatively low inflation rate of 5 per cent. He admits that the economy is likely to slow this year as exports – think textiles and phosphates – bring it particular grief. Still, he suggests that, within a few years, nearly every large French-speaking company will have an outsourcing centre in the country, to tap in to the large, well-educated workforce.

As with Mongolia, the big problem is that you can’t really invest directly in the place, unless you buy an apartment and then open a local bank account. Some of the private banks, such as Pictet, are active in the country. So are the MENA funds from the likes of Fidelity and GAM. But Tunisia is still too adventurous for most.

adventurous@ft.com