According to a report by the Bloomberg, energy firms, carmakers, aircraft and tobacco producers make the list of companies keeping an eye on Iran.
Bloomberg has listed 12 companies expected to invest in Iran after the possible lifting of sanctions against the country.
Aviation sector
American aircraft manufacture Boeing ,  which has already been granted a short-term license to export jet engine parts to Iran tops the list of major foreign companies willing to do business in Iran.
A preliminary agreement between Iran and the P5+1 group of countries in November 2013 led to an easing of sanctions on the aviation sector.
Boeing entered into an agreement with Iran Air in 2014, which generated $120,000 in gross revenues, the American company said then.
The deal included sale of aircraft manuals, drawings and navigation charts as well as data to the Iranian flag carrier airline.   
Earlier this month, an Iranian aviation official announced that Iran needs to buy up to 500 passenger planes in the next 10 years to renovate its aging fleet.
The world’s largest truck manufacturer Diamler GY, is also waiting on the outcome of nuclear talks between Iran and the six major world powers.
The German automaker abandoned a  30% stake in diesel-engine venture with Iran Khodro due to the sanctions banning foreign companies from trade with Iran.
French car manufacturers Peugeot and Renault have already started talks with their Iranian partners to resume operations in Iran.
Oil giants
Oil giants including BP (BP US), Eni SpA (ENI IM), Royal Dutch Shell (RDSA NA), Statoil ASA (STL NO), Exxon (XOM US), Schlumberger and Total  are also among the companies seeking to enter the Iranian energy market.
With eyes set on the removal of US-engineered sanctions in light of the progress in nuclear talks with P5+1, the country is already preparing for a potential influx of investors – specifically in its oil and gas projects.  
Iran holds the world's fourth-largest proven crude oil reserves and the second-largest natural gas reserves.
Iran’s total in-place oil reserves have been estimated at more than 560 billion barrels, with about 140 billion barrels of recoverable oil. Heavy and extra-heavy varieties of crude oil account for roughly 70-100 billion barrels of the total reserves.