Ten billion dollars.*
That’s the simplest answer to persistent questions about the price tag of a Boston Olympics, which has become a central issue in the emerging public debate about hosting the 2024 Games.
But settling the issue of the all-in cost may be as difficult as winning the 3,000-meter steeplechase.
A Globe analysis of bid documents drafted by local organizers suggests a Boston Summer Games would cost $9 billion to $10 billion to build, operate, and keep safe.
But that conspicuous little asterisk is the price tag for public transit improvements that the local organizing committee, Boston 2024, says would help the Games run more smoothly but are not required to host the Olympics and not in the budget.
Some of these transportation projects are already underway, while some may never happen. What portion of these improvements could or should be construed as Olympic-related costs seems a matter of debate.
The US Olympic Committee chose Boston last month to represent the nation in a worldwide competition for the 2024 Games. Boston 2024’s plan to pay for the event follows the traditional “privately financed” model used by US Olympic planners since the 1980s to avoid asking for massive, unpopular public subsidies.
The money to pay for the Boston Games, according to the plan, would come primarily from private sources, with the chief exception being security costs. Security would be picked up by the federal government and US taxpayers — or there cannot be a Boston Olympics.
The business-backed model is the most effective way to run the Games in the United States, said Peter Ueberroth, who led the profit-making 1984 Los Angeles Olympics and later served as commissioner of Major League Baseball.
“The private sector is much better skilled to do a sporting event than the public sector,” Ueberroth said in a Globe interview. “As long as it is private-sector-led, there should be no reason it affects the taxpayers, except positively.”
Smith College economist Andrew Zimbalist, an Olympic skeptic, says Boston 2024’s modest Olympic budget has been lowballed to hide the true costs of building a winning bid.
“The city and the state will have to pick that slack up, big time,” Zimbalist said.
Local organizers maintain that their budget, which includes $4.7 billion for operating costs, is conservative and realistic.
Revenue begins with the International Olympic Committee’s contribution to the host city, raised from IOC sponsors and broadcasting fees.
IOC president Thomas Bach, during a US visit to Arizona over Super Bowl weekend, said it is too soon to say how much the organization will contribute for 2024. “We have not yet concluded all our TV contracts and sponsorship contracts,” Bach said, though he suggested the contribution would be substantial. “We are contributing for Rio about 1.5 billion US dollars, plus marketing rights,” Bach said, referring to the 2016 Summer Games in Brazil. “It depends on income.”
Revenue estimates provided by the USOC project more than $1 billion in contributions from the IOC for the 2024 Games; about $1.1 billion in revenue from ticket sales for Olympic events; and more than $1 billion from domestic corporate sponsorships. Marketing, licensing and other smaller revenue streams cover the balance of the operating budget.
The revenue plan, while not dependent on public tax dollars, carries some risk for local organizers.
“The risk is that ticket sales don’t generate enough revenue, or there is not enough attendance, to pay for all the different projections,” said Laurence Msall, president of the Civic Federation, a Chicago public-policy organization that performed an extensive analysis of Chicago’s unsuccessful bid for the 2016 Games. “The other risk is with the sponsorship category, and whether you’re going to be able to draw the level of sponsorship in addition to the IOC’s sponsors.”
Building facilities for the Boston Games is expected to cost another $3.4 billion, according to organizers.
Under the plan, still conceptual, landowners would strike deals with private developers to build some permanent facilities, such as the international broadcast center, said Doug Arnot, an adviser to the USOC who is working with Boston 2024 to develop the bid. The developer would rent the building to Boston 2024 for the Games, and then lease or sell it afterward as a traditional commercial development.
“They’re going to do it or not because they see it’s a viable business venture,” Arnot said. “That’s the difference between US Games and other Games. We don’t build it and hope somebody comes along afterwards; somebody has to come along first. They build it. We use it. They take it back and they turn it into the legacy use.”
The Chicago 2016 plan called for the private development of a $1 billion athlete’s village on city-owned land, financed by the future sales of those units after the Games, Msall said.
Though he said there was “clear demand” for more moderately priced housing and high-end condos in the area, “our analysis said that was the greatest risk [of the bid]. It’s a real estate play at its core,” he said, and real estate markets can change suddenly.
Another potential risk is that the IOC wants Olympic Games to be guaranteed against financial shortfalls. Organizers will try to address the guarantee with multiple layers of insurance protection, Arnot said.
And, finally, security costs for the Olympics — having spiked since the Sept. 11, 2001, terrorist attacks — could be $1 billion to $2 billion, according to experts.
Olympic organizers are counting on the federal government to declare the Olympics a National Special Security Event, a designation that would put the US Secret Service in charge of security. The designation is used for public events that could be terrorist targets, such as political conventions and inaugurations.
Congress would need to appropriate money to pay for Olympic security, which “could be a tall order” if lawmakers want to make a high-profile symbolic stand against spending, said Jules Boykoff, an Olympic specialist at Pacific University.
Arnot said there is no risk that security costs would be transferred to local taxpayers — if the federal government does not handle Olympic security, no US city can host the Games.
“It would be utterly irresponsible for an organizing committee to assume antiterrorism responsibility,” he said. “No private organization is capable of that.”
Boston 2024, he said, will have to show “who is responsible for security and who is paying for security” when an IOC evaluation committee visits Boston in the spring of 2017, a few months ahead of the vote to award the Games. “There should be very little worry about this because it’s binary — we’ll have it or we won’t.”
Not included in the budget for the Games are the costs of transportation and infrastructure improvements, which are paid for with public money.
Local Olympic organizers insist the city has nearly all the infrastructure it needs to effectively compete for and host the Games because of three recent projects: the Big Dig, expansion at Logan Airport, and the Deer Island harbor cleanup.
Boston 2024 chief executive Rich Davey, a former state transportation secretary, said only one additional transportation project is absolutely necessary to host the Olympics: the MBTA’s planned acquisition of new Red and Orange line cars, which will increase reliability and ridership capacity, he said. The state last year selected a Chinese company to build the new cars; the selection has been challenged in court by losing bidders.
In addition, Boston 2024 has cited three dozen other infrastructure projects that would enhance the Games but, Davey said, are not required. Almost all of these projects were already on the wish list of some public agency before Boston became an Olympic contender, such as a planned expansion of South Station, extension of the MBTA Green Line, and rail service linking the Back Bay and the Boston Convention and Exhibition Center.
Local Olympic planners have promoted the bid as a way to spur state investment in infrastructure, which may seem at odds with Boston 2024’s insistence that the only improvement it desperately needs is already taking place.
Davey acknowledged “it certainly can get confusing . . . I think perhaps we haven’t done a good enough job about talking about what the Olympics costs.”
Mark Arsenault can be reached at Mark.Arsenault@globe.com.