Iran has appointed a 27-year-old holder of a doctoral degree in management as head of its bourse, where stocks have been dropping, a stock exchange official told Reuters on Monday.
Bourse chief Hossein Abdoh-Tabrizi resigned last week, after the all-share index lost 20 percent since June.
"The stock market board has appointed Mr Ali Salehabadi as secretary-general of the stock exchange," said Jamshid Zakeripour, secretary to the bourse secretary-general.
President Mahmoud Ahmadinejad has prided himself on a management system that brings idealistic and devout young people into positions of power. He is overhauling the posts of nearly all of the country's economic and political policymakers.
Ahmadinejad said in his presidential campaign broadcasts that the young and enthusiastic were better choices but would have a 30 percent "error rate".
Salehabadi has a doctorate in management from Tehran university and ran the stock exchange branch in Karaj, a satellite city to the west of Tehran, for about a year.
The board of the bourse had picked former deputy commerce minister Mohammad Nahavandian to be the new secretary-general but he turned the job down at the weekend.
"Since I have some standing commitments and current responsibilities and have always emphasised the importance of expertise, I will not be able to accept this responsibility for which I apologise," the official IRNA news agency on Sunday quoted a letter from Nahavandian as saying.
Investors have been bailing out of Iranian stocks in recent months, concerned over Ahmadinejad's economic policies and growing international pressure over Iran's nuclear programme.
"As soon as Iran's nuclear dossier is settled, calm will return to the stock exchange and it will recover," Salehabadi was quoted as saying by the ISNA students news agency.
Iran faces referral to the UN Security Council for possible sanction after failing to convince the world that it is working on atomic power stations rather than on warheads.
The bourse lists 428 companies and is valued at about $37 billion.
Market authorities announced plans in April to allow foreigners to buy up to 10 percent of firms listed in Iran. However, they would be able to repatriate their capital gains and profits only after three years.