Investors in all parts of the UK will face increased costs if Scotland votes for independence, Hargreaves Lansdown has warned.
Sterling tumbled in overnight trading and was poised for further losses today after the latest poll showed Scotland is on course for independence.
One of Europe's top officials has said Scotland will not be allowed to keep using the pound sterling and remain in the European Union in case of an independence vote.
The managers of the Ruffer investment company have defended their portfolio's exposure to the US dollar, saying it will protect them against a trio of political events which could knock back sterling.
Housebuilder stocks have fallen and the pound is nearing 1.70 against the dollar as investors react to Mark Carney's change of tack on interest rates and new measures that may curb mortgage borrowing.
Stock markets have jumped this afternoon following a series of drastic measures from the European Central Bank to stave off a downturn and boost inflation.
Sterling has fallen back below $1.69 after worse-than-expected borrowing figures disappointed those investors hoping for further confirmation the economy is back on track.
Sterling has spiked further against the dollar and other currencies after strong retail sales and minutes of the latest Monetary Policy Committee meeting stirred up the rate hike debate.
An independent Scotland would face a "capital flight" if it did not retain the pound, according to analysts at Deutsche Bank.