Major League Soccer has been called everything from the future of American pro sports to a Ponzi scheme.

Which label fits? That's an important question for Greater Cincinnati as the owners of Futbol Club Cincinnati shake the trees on both sides of the Ohio River for $100 million in public money to help them land an MLS expansion team.

FCC owners are bringing $250 million of their own cash, big names from the area's business community and promises of economic benefits, but they won't share financial details of the team or the league – even as they ask for taxpayer assistance.

Meanwhile, interviews with sports business experts, observers and even league officials paint a complicated picture of MLS' current and future financial status. That future is fraught with pitfalls such as a comparatively small TV deal, the risk of overexpansion and continued red ink.

But the league could also see a big payoff down the road.

Attendance now exceeds that of pro basketball and hockey on a per-game basis. TV ratings have continued to grow despite remaining much lower than other American sports. And the reach of the league expands as it continues to add teams.

League officials are bullish on the future, even though MLS hasn't turned a profit in more than two decades.

"If you take a look at the 22-year history of the league and the trajectory of growth particularly in the last five years, we are uniquely positioned to take advantage … of the growing market for soccer fans," said MLS Deputy Commissioner Mark Abbott, who helped create the league's initial business structure in the 1990s. "Some 79 million people engage with pro soccer in some way in this country."

FC Cincinnati would seem to be proof of soccer's potential. The owners and operators have captured the attention of not only the area but the entire sport with its success both on the field and in the stands as a United Soccer League team, the equivalent of a AAA baseball team.

But the club's backers will need to pay a steep $150 million entry fee if MLS selects FC Cincinnati to be one of two new expansion teams in December and $100 million for a soccer-only stadium, and find a community to pony up the other half of the stadium cost. Despite the popularity of FCC's current home, the University of Cincinnati's Nippert Stadium, MLS is insisting that all expansion teams commit to having soccer-specific stadiums.

Team officials won't discuss how much money they could make or other financial details, instead focusing on what a team could do for the area.

"This is a legacy investment," said Jeff Berding, FC Cincinnati's general manager, president and co-owner.

Berding, a former Cincinnati councilman, also worked in marketing for the Cincinnati Bengals previously.

"We are investing in this to make Cincinnati a better place for our children and grandchildren. Soccer is the only sport that really allows global promotion of your city … and as we compete in a global economy for jobs, talent, companies – we need to have soccer."

Some outside observers aren't so sure whether those promises of growth can be kept. As with FC Cincinnati, the league keeps financial details private, making projections about the future impossible.

"The league's finances are completely opaque and there is no reliable information anywhere – so that makes it really hard to believe they are on this incredible growth curve that will make everyone rich," said Stefan Szymanski, a sports management professor at the University of Michigan and founder of the Soccernomics consultant firm.

Szymanski was the one who called the current arrangement a Ponzi scheme in a now-infamous article earlier this year for the online sports site Deadspin.

"I wasn't calling the MLS a fraud...but the way they are handling these expansion fees certainly looks like a pyramid scheme," he said.

That risk is top of mind for area political leaders who are being asked to help build a soccer stadium in either Cincinnati or Northern Kentucky.

"We haven't delved into the particulars, but whether or not there will be a league in 20 years is certainly a question that has been raised as we examine this," said Hamilton County Commissioner Todd Portune. "In fact, it's one of the big questions our financial consultant says we should get answered before we commit."

FC Cincinnati is also considering a site in Newport across the river in Kentucky for a stadium. Officials there have consistently refused to comment.

The Enquirer tried several times to contact FC Cincinnati Chief Executive Officer Carl Lindner III, the primary owner, but he declined through a spokeswoman. She said his various business interests did not allow time for an interview.

But Lindner found time to write an op-ed for The Enquirer asking for public support of a stadium in the area to help land the MLS bid next month.

"We have transcended from a start-up and created a culture fueling record crowds that will leave a lasting legacy," wrote Lindner, the son of former Cincinnati Reds majority owner Carl Lindner and the former co-CEO of American Insurance Group. "Greater Cincinnati governments have a strong history of collaborating...through public-private partnerships. These partnerships are necessary when public or private dollars alone cannot finance the progress we want for our region."

The Enquirer also tried to interview other members of the FCC ownership group, including oil and gas company owner Stephen Hightower, venture capitalist Jack Wyant, car dealership owner George Joseph, Cintas CEO Scott Farmer and American Insurance Group CEO David Thompson. They either did not return messages seeking comment, declined comment or deferred comments to Berding.

For his part, Berding steadfastly declined to discuss current or potential future revenues or financial projections for FC Cincinnati if the club wins the expansion bid.

"Cincinnati wants to be in the first tier of American cities for jobs, companies and exposure...but it needs soccer to do that," he said. "When there are international videos and promotions about pro soccer being made and if we are an MLS team, it will be FC Cincinnati that is listed – the name of the city."

FC Cincinnati fans vocally expressed their enthusiasm at a Hamilton County commissioner's meeting in late September. But many in the community are skeptical of the idea of using taxpayer money on a soccer stadium, especially with a lingering hangover from the county's previous stadium deals with the Bengals and the Reds.

"Here we have a league that hasn't turned a profit in 20-30 years and yet we're supposed to use taxpayer dollars to pay for the future," said Jeff Capell, an economist from Blue Ash who has spearheaded opposition to new stadium taxes for Hamilton County.

"If the owners of FC Cincinnati think it's such a great investment, let them put their own money into it."

Born out of the successful World Cup hosted by the United States in 1994, MLS is the latest iteration of U.S. pro soccer, following leagues that came and went through the years.

But MLS operates unlike other American sports, where individual team owners came together to form leagues – and where the individual teams are separate companies that have individual contracts with their players.

Instead, MLS formed from the middle and then spread out. It's considered a "single-entity" league, operating as a company with individual teams acting as local subsidiaries. That means the league, not the team, owns the contracts with the players for example. The league also decides which marketing rights local teams can pursue on their own and which should be league-wide.

"That gives the (club) owners a degree of strategic control of the league as a whole in whatever business environment may exist at that particular time," MLS' Abbott said. "For example, we used to split ticket revenues 50-50 between the league and the clubs, but the owners came together made the decision that it should be 70 percent to the clubs to help incentivize further investment at the local level."

But other experts say the business model has hampered growth and potential profits.

"That model has some problems with it and is one of the reasons why it has taken MLS as long as it has to develop significant momentum," said Andrew Zimbalist, a sports economics professor at Smith College.

Still, Zimbalist said that "soccer in the U.S. is a sport that has to be taken seriously" – because of its longevity, growing popularity, ability to get new stadiums and high sale prices.

League officials acknowledge that the league as a whole hasn't turned a profit since that first game 21 years ago.

TV deals, the lifeblood of most sports, bring soccer a fraction of the money that other pro sports net – $90 million a year for MLS vs. $2.7 billion for the NBA and $200 million for the NHL, for instance. And there's uncertainty about how much MLS can command next time after the current deal expires in 2022.

Still, MLS has managed to grow in fits and starts, with some franchises going out of business while others see profits. Miami and Tampa Bay shut down and merged into one team in 1999, but teams are thriving in Seattle and Kansas City.

MLS officials declined to divulge any financial numbers. But recently, Forbes reported that clubs are worth about $223 million on average based on revenue estimates, reported TV contracts, deals for naming rights and other publicly available financial information. That average value is up from $37 million in 2008.

The league earned nearly $650 million in revenue in 2016, or an average of about $32.5 million per club, the magazine reported. The revenues informally rank MLS as the world's 15th most valuable pro sports league.

Berding said if FC Cincinnati doesn't land a team this time, the cost of entry will probably go up to $200 million or more next time.

As for the future of the league, many point to demographic trends that indicate possible long-term success that could put the MLS on par with the NFL or NBA. One key sign: the popularity of the video game based on international soccer.

"It's not crazy to think that at some point over the next 10,0 20 or 50 years that MLS could be at the level of the NFL and the NBA," said Don Cornwell, a banker and sports finance expert for PJT Partners. He has advised the NFL.

"I would bet more kids in the U.S. know the starting lineup for (European soccer power) Real Madrid than the average Major League Baseball team" because of the video game, Cornwell said.

But the league also lost a huge marketing and exposure opportunity when the U.S. men's national team – made up of mostly MLS players – failed to qualify for next year's World Cup in Russia.

Some think MLS is actually growing too quickly. The danger there is in diluting the brand in exchange for a quick infusion of cash – an issue that led to the demise of NASL, the league's predecessor.

Two clubs started this season, and another is set to start in two years. (Miami also is trying to add a team but that's still up in the air). And then MLS will hand out two expansion bids in December for teams that will begin play in 2020.

"It's a real balancing act they are walking here with all this expansion," said University of Southern California sports business professor David Carter. "They need to be keeping their eye on their long-term capital investment."

So back to that league entry fee.

Deadspin and Szymanski raised a lot of eyebrows with his Ponzi scheme reference, especially since other sports leagues ask for large expansion fees from new teams. Yet he remains steadfastly skeptical about the future of the league.

"It looks like any new money coming into the league is subsidizing current and previous losses – like new money propping up existing owners," Szymanski said. "And they have tried to create a closed system when the market for players is international. This is clearly second-tier soccer, and the best talent goes elsewhere.

"Even those attendance figures they like to tout include a lot of free giveaways."

League officials and others defend the entry fee, saying the fee is basically buying a slice of MLS. Abbott said the money will be invested in the league and other uses to be decided by existing team owners.

"New owners become part owners of MLS as a whole and thereby get decision-making powers as well," Abbott said. "And those decisions include how to best invest any new income streams."

Berding wouldn't discuss which owners are putting in how much toward the fee and declined to discuss MLS's ownership structure – or what the league has told the team about future projections.

"The structure is the structure," he said.

FC Cincinnati's owners have weighed the risks vs. the rewards and are willing to plunk down $250 million. Whether that's enough to convince for local politicians and taxpayers to kick in $100 million remains to be seen.