It’s no secret that Catalonia, whose capital is Barcelona, has been considering breaking away from Spain and going it alone. And certainly the movement has gained impetus after Scotland’s vote on leaving the U.K.

However, the discussion has taken on new and troubling overtones since a nonbinding vote on the issue in Catalonia on Nov. 9. While popular opinion appears to come down increasingly on the side of independence, providing a corresponding increase in popularity for Catalan President Artur Mas, who presided over the vote, Catalonia—and Mas—have other troubles. Mas is not popular at all with the government in Madrid, which appears to be squaring up for a fight over the matter.

When the Spanish constitutional court declared the originally scheduled binding referendum illegal, Mas and Catalan independence supporters decided to proceed instead with a nonbinding vote. The constitutional court then declared even that was illegal, and ordered that it be postponed until the issue could be further examined.

But the vote proceeded, with 2.3 million people voting out of a total Catalan population of 7.4 million. And 80% of those voters supported a move to independence.

At stake, along with the issue of greater overall autonomy, is Catalonia’s control—or current lack thereof—over taxation. Both the Basque region, which has been agitating for decades for its own independence, and the region of Navarre have considerable autonomy over the setting and collection of taxes, and are permitted to keep most of the taxes they collect.

But Catalonia, the second most populous region in the country, as well as the wealthiest—it is home to some of Spain’s largest companies, and accounts for 193 billion euros ($241 billion), or about 20% of Spain’s GDP—does not.

Spain’s central government is firmly opposed to independence for Catalonia. Since the nonbinding vote, Spanish Prime Minister Mariano Rajoy solicited the help of the attorney general’s office to determine whether any crimes were committed when the vote proceeded against the constitutional court’s orders. As a result, Spanish prosecutors have charged Mas with disobedience, perverting the course of justice, misuse of public funds and abuse of power.

That, however, has only increased the independence fervor in Catalonia—which could have a detrimental effect on the Spanish economy as a whole, and wider implications for the European economy should the region decide to go it alone. In fact, pro-secession party Esquerra Republicana is hoping to convince Mas to lay out a path to independence that would allow Catalonia to take over control of tax collection in the region in 2015, with full independence within two years.

Fitch Ratings has analyzed three potential scenarios for how the economics of Catalonia’s quest for independence could play out. They range from negative ratings that would result from outright separation to potential positive ratings from greater autonomy in the region.

Fitch said in its report that over the medium term, up to the end of 2016, devolution is the most likely scenario, with “the central government and Catalonia negotiat[ing] further economic devolution. The precedents for this are the Basque Country and Navarre, which have large tax-setting powers and keep most of the tax they collect.”

That, in fact, would probably have a positive effect. Fitch said, “If negotiations led to further fiscal autonomy, Catalonia’s fiscal revenues would increase, as it is a net contributor to the central government. It would also be likely to benefit from continued access to central government support. The impact on the sovereign and the region would probably be mildly positive because it would have eased one source of political risk over the medium term.”

Fitch added that, if Catalonia were granted an increase in fiscal powers, “We believe it would address some of the structural problems resulting from the underfunding of essential public services and the reliance on cyclical fiscal revenues such as taxes on property transactions, and should be credit positive…. This scenario is also the lowest risk for other Fitch ratings, such as corporates and banks. Large corporates may benefit because their cost of funding would fall and there would be an increase in foreign direct investment following a positive resolution of the conflict.”

The lack of a negotiated settlement of some kind over the next two years would likely result in “the political frictions between Spain and Catalonia … likely [continuing] or even escalat[ing]. If there were early elections that returned a more pro-independence Catalan government but there were no change in the status quo, risks may simply build up.”

Fitch added, “We believe protracted uncertainty and heightened tension could trigger some near-term deposit outflows, particularly affecting Catalan banks, increase the cost of funding and drive corporates to reduce capex in the region as a protective measure. Banks’ liquidity risks would be reduced by access to the European Central Bank’s liquidity facilities, while most Fitch-rated Spanish corporates have solid funding positions.”

The most negative outcome with regard to ratings, Fitch said, would be independence. “Catalan independence would most likely have negative consequences for Spain and Catalonia’s rating. Even an orderly breakup of Spain would pose risks to the national economy, and a disorderly breakup much more so. In a disorderly breakup, in which Catalonia gained independence at the cost of leaving the European Union and eurozone, these risks to both Spain and Catalonia would be exacerbated.”

While Fitch said that there were numerous ways in which a separation could occur, some factors would be common to all, such as splitting the national debt. “A similar solution to that proposed by the U.K. regarding Scotland would lead to Spain (excluding Catalonia) honoring all outstanding Kingdom of Spain bonds. As Catalonia represents 18.8% of Spanish GDP, Spain’s general government gross debt/GDP ratio would therefore jump to over 120%. This would probably be offset by an equivalent bilateral claim on the Catalan government, but the Spanish sovereign would be highly exposed to Catalan credit risk.”

A disorderly breakup could result in the exit of Catalonia not just from Spain, but also from the EU and the eurozone, “which would exacerbate” risks to the national economy. In addition, independence would “increase the credit risk faced by banks with particularly large exposures to Spanish sovereign debt and could feed through more generally into banking sector funding costs and liquidity.”

Fitch said that companies based in Catalonia might “export capital to other eurozone countries, especially Spain. The subsequent economic stress in the region might increase delinquencies in structured finance asset portfolios.” Legal and regulatory uncertainties could also be in the wings for such things as regulatory frameworks for electricity and gas assets. Corporates could cut capex in the region, and “companies holding long-term concession agreements such as toll roads” could face similar challenges.

In addition, “interest expenses could increase due to perceived higher risk and potentially higher sovereign yields, especially for companies with a significant exposure to Catalonia.”

Currently Fitch has given Catalonia a long-term issuer default rating of BBB-, “based on the central government’s support through various instruments, including access to the regional liquidity fund (FLA). However, in September the ratings agency “placed the rating on Rating Watch Negative … after tensions between the central and regional government increased due to Catalonia’s unilateral call” for the nonbinding vote on the region’s future.