MADRID/BARCELONA, Nov 22 (Reuters) - Industrious Catalans widely believe their world-class companies and export-strong economy - almost the size of Portugal's - would be better off without the rest of Spain.
As the region prepares for regional elections that may set it on course for secession, that contention is being tested by a raft of reports into the financial fallout of a split of Europe's fifth biggest economy.
It would take years to happen and businesses themselves are reluctant to discuss the possibility publicly, but privately senior managers say they are deeply concerned at the risk Catalonia could be forced out of the EU, even were it only for a time.
Other problems relate to the scale of Spain's - and the region's - existing debt problems as well as how much more it may cost banks and companies to find funding outside the euro zone.
"Economists are taking part in a war of statistics," said Pere Puig Bastard, economist at Spain's ESADE business and law school. "From an economic standpoint, it's impossible to establish the impact of how long we would live in legal limbo and it's a bad time to be hitting investments."
A growing number of the northern region's 7.5 million people want to break away from Spain as a recession fosters frustration over a tax structure by which Catalonia pays an estimated 16 billion more to Madrid than it receives in return.
Sunday's regional election is expected to re-elect the conservative Convergence and Union party, whose leader Artur Mas pledges to hold a referendum on independence.
Ramon Tremosa, a CiU member of the EU parliament, says the region's export prowess would allow it to catch up with some of Europe's wealthiest areas and deal better with a crisis of debt and recession from which Spain is struggling to emerge.
"A new Catalan state would force Madrid's bureaucrats to get back to work. After five years of crisis, Spain has no exit strategy and no idea how to get out," Tremosa said.
The pro-independence lobby says if Catalonia, which accounts for a fifth of national output, were freed from the tax burden of belonging to Spain it could invest in its own infrastructure and boost production.
But it would first have to deal with its own effective insolvency - broke after overspending in a decade-long building boom, Mas had to reach out to the central government for 5 billion euros in aid earlier this year.
Like Scotland, set to hold a referendum in 2014 on leaving the United Kingdom, it will also have to take on its own share of a national debt that should top 85 billion euros this year.
The region faces debt redemptions of about 6 billion euros next year, and will probably have to get financial help from the central government again.
All of those problems, if they are still unresolved by the time a referendum is held, will look a lot less daunting if there is a guarantee of a smooth, unbroken shift into full EU membership after independence.
But under European Union rules, a breakaway republic would have to go through a potentially lengthy process of applying for membership in the bloc after seceding, and the concern of ordinary Catalans and businesses is palpable.
Polls show that between 46 percent and 57 percent of Catalans want independence from Spain. But the surveys also show that support for independence falls by as much as 10 percentage points if independence implies exiting the European Union.
"Were Catalonia not a part of the European Union, that is not desirable," said a source from a large Catalan company who asked not to be named due to the sensitivity of the matter. "This is a major condition that might act as a restriction to real independence."
The pro-independence movement says that if Catalonia held a referendum and a huge majority of Catalans voted for their own country, the European Union would have to respect the right to self determination. Officials say both they and the Scots are lobbying hard on these issues in Brussels.
Catalonia is home to some of Spain's largest companies, including engineering group Abertis, airline Vueling , publisher Grupo Planeta and banks CaixaBank and Sabadell.
Almost a third of Spain's exports come from the region, which has drawn in more than 3,000 multinational investors including Volkswagen, Renault, Dow Chemical and Sony.
As a member of the EU, union citizens enjoy virtually passport-free travel, companies can trade freely covered by cross-border regulation and industries enjoy single regulatory rules translated across the 27 member states.
The change in status could also disrupt the region's role as Spain's logistic gateway to the rest of Europe. In 2007, just under half of Catalan exports went to the rest of Spain while more than 80 percent of the remaining exports were sent to EU countries, according to Spanish trade analysis group C-intereg.
"(Export companies) would be hugely penalized. Businesses now based in Catalonia would have a big incentive to move just inside the Spanish border and thus access the common market," Swiss bank UBS warned in a report.
While Catalonia could adopt the euro - like, say, Kosovo - without being officially inside the monetary union, question marks would still hang over the ability of the Catalan state and companies to raise funds from outside the euro zone.
None of that means companies are guaranteed to up and leave, the Catalans say, but it means there are issues to address.
"What Catalonia's big companies are concerned about is not independence. It's the process, the transition that worries them," said Jordi Pujol, who was the president of Catalonia from 1980 to 2003 and is one of the founders of the CiU party.