Now that there's a framework that could lead to an overarching nuclear deal with Iran, global investors who were lining up at the gates are getting ready to move in.
Inside of Iran, business leaders are waiting with open arms.
The Tehran Stock Exchange is down 4.5 percent so far this year but the top executive at one of Iran's biggest investment firms says the market is about to take off.
"Once a final deal is reached Iran will be open for business" said Ramin Rabii, CEO of Turquoise Partners. "Hundreds of millions of dollars, maybe even billions, will pour into Iran's economy."
Rabii believes the sector that will jump the fastest and the most will be Iran's financial industry. He said that banks, which were hit hard by sanctions, will move up fast once the restrictions are lifted.
"That will have a huge impact on the country," he said. Some 15 percent of Turquoise's funds are invested in the sector now, but Rabii plans to grow that.
He also said the Islamic Republic's petrochemical sector will be an immediate benefactor of evaporating sanctions.
"Global insurers left this market due to international restrictions; they will come back quickly," Rabii said. "The sector will benefit from global financing and new technologies that the sanctions kept away."
The optimism goes well beyond Turquoise. Other investment managers agree that Iran's energy and financial sectors will get a fast boost, and some expect the country's steel and iron ore businesses to improve, too.
Outside of Iran, not all experts are as optimistic. "It's too soon for any major economic relief in Iran," said Alireza Nader, an expert on Iran's powerful Revolutionary Guard at the Rand Corporation think tank.
He believes any economic improvement will be gradual although a psychological barrier has been toppled.
"However, Iran has tremendous economic potential," Nader said. "If sanctions are lifted and if some of the structural issues with the economy are addressed, such as over-reliance on oil and the unaccountability of the Revolutionary Guards, then Iran may see tremendous growth. But it's too soon to know if that will be the case."
Despite that note of caution Rabii of Turquoise says he's overjoyed. "I've been waiting for this day for almost 10 years," he said. "Iran is in for a good ride."