​Why markets are "het up" on Scotland's independence vote

Yes and No campaigners wait for the departure of Labour leader Ed Miliband on the Scottish independence campaign trail on Sept. 4, 2014, in Blantyre, Scotland. File.

Jeff J Mitchell/Getty Images

When it comes to Scotland's future, more of its residents are feeling the itch to go it alone according to a new poll, and that's rattling more than just the supporters of a unified U.K.

The Scots will vote on Sept. 18 on whether to sever ties with England, Wales and Northern Ireland. While the polls had previously indicated that the vote would keep Scotland squarely within the U.K.'s realm, that's apparently shifted, with a YouGov poll this past weekend finding more Scots are now leaning toward standing on their own.

That's rattled the markets, sending the British pound close to a nine-month low against the U.S. dollar and putting pressure on Scotland-linked stocks, such as the Royal Bank of Scotland (RBS). While the question of whether the Scots should gain their independence might cheer fans of "Braveheart" and its independence-minded hero, the 13th century Scots warrior William Wallace, the implications of splitting from the U.K. extend far beyond the British isles.

"If this becomes a reality, it will embolden every other disgruntled European region to secede from their parent country, aka Catalonia and Spain to name one," Peter Boockvar, the chief market analyst with economic advisory firm The Lindsey Group, wrote in a research note. "From an economic perspective, a breakup of the U.K. will be disruptive but to what extent is a definite unknown."

If Scotland breaks up with the U.K., it would end more than 300 years of a united Scotland and England. The two countries merged in 1707, when the Acts of Union created Great Britain. While both countries had been ruled by the same monarchs for a century before that, the 1707 act established economic principals -- such as free trade throughout Great Britain -- that helped establish greater financial security for both countries.

With a potential dissolution of the union, a host of questions are bubbling up, and, not surprisingly, many of them relate to economic issues, such as whether will Scotland continue to use the pound. But many of the questions don't have clear answers, which is adding to investor and market uncertainty.

Take the issue of the U.K.'s currency, the pound sterling. Scottish First Minister Alex Salmond, in a white paper arguing the case for the split, wrote that an independent Scotland would "share the pound for our mutual benefit."

Not so fast, says George Osborne, the U.K.'s chancellor of the exchequer. In a recent appearance on a BBC show, he said, "No ifs, no buts, we will not share the pound if Scotland separates from the U.K.," according to the U.K.'s The Independent newspaper.

It's also unclear how much U.K. national debt Scotland would take on, as well as whether an independent Scotland would adopt the euro. Given that Scotland believes "membership in the EU is in the best interests of Scotland," it might be forced to accept the euro as its currency, professor Jo Murkens told the Scottish Express.

Still, some analysts doubt that the Scots will vote to leave the United Kingdom, citing uncertainty over these economic issues.

"Our basecase remains that Scotland will vote to stay in the U.K. on September 18 given the continued uncertainty over currency, the workings of the financial system, EU and NATO membership, defense, student funding, pensions and welfare, as well a majority of Scots' desire to remain part of the union with the rest of the UK," wrote Eurasia Group's Mujtaba Rahman and Charles Lichfield in a research note on Monday.

Meanwhile, Scottish business leaders are urging their countryfolk to vote against independence, stressing the economic risks of going it alone. More than 130 executives at companies such as BHP Billiton and HSBC bank published a letter last month in the Scotsman newspaper calling for the United Kingdom to remain intact.

"Uncertainty surrounds a number of vital issues including currency, regulation, tax, pensions, EU membership and support for our exports around the world; and uncertainty is bad for business," the letter noted.