Barclays bank has warned that the upcoming vote on Scottish independence could "affect the group's risk profile" by potentially destabilising financial markets.
Barclays' warning follows concerns expressed by several other financial institutions about the effect of the independence vote, including Lloyds Banking Group, RBS and Standard Life.
Barclays said: "The referenda on Scottish independence in September 2014 and on UK membership of the European Union (expected before 2017) may affect the Group’s risk profile through introducing potentially significant new uncertainties and instability in financial markets."
Barclays said the vote could bring uncertainty "both ahead of the respective dates for these referenda and, depending on the outcomes, after the event".
Scotland's Finance Secretary John Swinney has said the warning by Lloyds Banking Group about the possible "risk" from independence backs up the case for a "formal currency area".
Swinney said: "Scotland has a strong and diverse economy and the point of independence is to win the powers we need to build on those strengths and create a more prosperous and secure economy - which is good for the financial sector and everyone else.
"Lloyd's Banking Group's comments show exactly why our proposals for a formal currency area are the right proposals, why they are in the best interests of business on both sides of the border and why that is what will be implemented by both governments."
Lloyds Banking Group has said that Scottish independence poses "no immediate issues" to its business, after warning that separation could present a "risk" to its operations.
A spokesman for the group said: "Lloyds Banking Group believes that questions about Scotland’s future constitutional position are a matter for the people of Scotland and the UK and Scottish Parliaments.
"There are no immediate issues that will affect Lloyds Banking Group customers either in Scotland or the rest of the UK, particularly as any change in constitutional arrangements are unlikely to come into effect until 2016."
Lloyds Banking Group has warned that Scottish independence poses a potential "risk" to its business.
It listed separation in its annual report as one of the seven key risks in the months ahead.
Pensions and savings firm Standard Life has already issued its own warning about independence, saying it plans to leave Scotland if Scots vote for separation, and "if anything were to threaten" its business.
Lloyds' warning follows similar concerns expressed by RBS that independence poses unknown risks to its business.
Lloyds Banking Group has said it will address "historic issues" in the taxpayer-backed bank after being fined a record £28 million from city regulator, the Financial Conduct Authority (FCA).
In a statement, Lloyds said:
"Lloyds Banking Group accepts the findings of an FCA investigation into its historic systems and controls governing bancassurance legacy incentive schemes for branch advisers, and has agreed to pay a fine of £28m.
"The Group launched its new strategy in 2011 to fully refocus the business on its customers. As part of that approach, the Group has been addressing historic issues and ensuring that customers get fair and appropriate outcomes.
"Lloyds Banking Group has co-operated fully throughout the enforcement investigation and has agreed with the FCA the next steps with regard to customers."
In a speech to assembled Lloyds Banking Group staff in Birmingham, Chancellor George Osborne thanked employees for putting up with "difficult decisions" and job restructuring since the 2008 government bailout.