Renaissance Capital's Global Chief Economist Charles Robertson has visited Iran back in March 2014 and published an interesting report after his visit.
"The past 10 years have seen global investors reach into previously untapped markets, from local-currency corporate bonds in emerging markets to equities in frontier markets ... We believe Iran would represent the last such opportunity globally, in an investable scenario. No other country is as large or as untapped."
"Unlikely as it may sound, stock market capitalisation is roughly $170bn (similar to Poland) after a wide-ranging privatisation drive over the past decade. The free float on the main market is closer to $30bn, which is above the MSCI free floats of Kuwait and Nigeria. This would make it equivalent to roughly 25% of the MSCI frontier index if all companies qualified for inclusion. On the local exchange's data, daily trading volumes are around $150mn. This compares with $26mn in Nigeria in 2013. There are no Iranian barriers to foreigners investing in the market: foreign brands from Coca-Cola to Danone are in the country."
If you need to see case studies of foreign companies already active in Iran, check our Directory of Foreign Companies in Iran.