While the frosty relations between the U.S. and Cuba have thawed slightly, much more needs to be done to fully realize the opportunities in the Cuban marketplace.

According to a study by Marguerite Fitzgerald and Enrique Rueda-Sabater from the Boston Consulting Group entitled “What Cuba’s Economic Evolution Means for Multinationals,” the authors conclude that Cuba will need to take comprehensive measures to overcome structural limitations on its economy by improving infrastructure, attracting foreign capital and continuing to open its markets. In turn, the U.S. government can help by further easing trade and travel restrictions.

Even though there is a lot of uncertainty surrounding Cuba, understanding the issues and potential growth opportunities can help “multinational firms and foreign investors to stake an early claim in an untapped market,” the study said.

The report estimated Cuba’s GDP growth rate at 2 percent to 4 percent annually over the next five years, although it believes this could be a conservative projection given that GDP has risen 5 percent to 6 percent annually in recent years. In 2014, GDP hit $82 billion, and with 11 million people, Cuba is regarded as one of the largest economies in the Caribbean. Limiting the opportunities have been the ongoing U.S. embargo, which prohibits American companies from trading with Cuba unless they obtain a permit from the U.S. government, and Cuba’s poor human-rights record. While some countries — China, Venezuela and Russia — have had trade relations with Cuba, many European nations have chosen not to due to potential implications for their activities in the U.S. The BCG report also noted that the Cuban government has plans to unify its two currencies — the Cuban peso is used by Cubans, while the Cuban convertible peso is meant to be used by foreigners as it’s pegged to the U.S. dollar. While that’s a positive step toward transparency, it might be difficult to do since it means resetting the value of financial assets owned by individuals and institutions.

Fitzgerald said in an interview that the average wage — most Cubans work for the government — is $20 to $25 a month. She also said many Cubans, about 40 percent, receive money from friends and family outside the country. “The extra cash gives them a desire to spend on other things, even though it may be a struggle to get basics at the food store. Many will buy a nice pair of runners or [some] electronics [item],” she said.

The BCG study said the U.S. has increased the cap on remittances that American-based individuals can send to Cubans, which right now is up to $2,000 in a three-month period to nonfamily members, although there is no cap on amounts sent to family members. The study said that remittances from the U.S. grew 15 percent a year from 2010 to 2014, to about $3 billion. In comparison, Cuba’s net exports in 2014 were less than $4 billion, the report noted. The BCG report projects that remittances from U.S. citizens could grow to $6 billion by 2018, although remittances and private enterprise so far have been concentrated in wealthier areas in the north, primarily in Havana.

In 2010, Cuba initiated some market-based reforms that eased the rules regarding self-employment and private ownership. The move expands beyond the previous rule that limited entrepreneurship to service professions. The reform allows startups to hire up to 25 employees. The Cuban government has also eased the restrictions on the ownership of private property.

But even as changes, from easing of market restrictions in Cuba to President Obama’s visit to Havana this spring, suggest momentum for accelerated growth in the longer term, there are still roadblocks ahead.

One big question mark is the U.S. election. The report said there is no guarantee that warmer relations with Cuba will continue. “Several candidates in the U.S. presidential-election primaries have openly stated that they oppose the current thaw,” the report said.

Further, even though Unilever said it plans to open a factory in Cuba, the country’s economic growth is likely to be slowed by structural limitations. The country has limited activity on the manufacturing front, and decades of underinvestment have left Cuba with a decayed infrastructure. Fitzgerald said there is “only one major port where product is imported into the country. When the port gets blocked, you can’t get product out and so you have fresh product wasting in the port. There’s no truck and no roads to get the goods in.”

Information and communications technology are also limited. Further, Cuba has an aging population as low birthrate and increased emigration to the U.S. have left the country with “distinct ‘holes’ in its young and middle-aged populations.”

Based on BCG’s research, Fitzgerald said it is “very unlikely there will be big political changes,” over the next few years, although she said anecdotally that change is expected when Raul Castro leaves the presidency in 2018.

Castro’s departure will mark the end of his family’s reign, which began with his brother Fidel in 1959.