Clients of Canaccord Genuity have launched legal action against the firm over potential tax liabilities arising from the use of film partnership products sold between 2006 and 2009.
An unknown number of clients have launched two pre-action protocols, which offer litigants a chance to head off court proceedings via mediation, but may also precede a civil court hearing if they are unable to reach agreement.
A company spokesperson said: 'The advice related to these investments was given at a time that preceded our firm’s acquisition of a small wealth management operation.
'Importantly, our clear view is that clients have received appropriate advice and support in respect of these investments.
'The arrangements in question were all backed up by independent, expert advice and outside opinions and clients were fully supported in understanding the nature and risks of the investments that they made.'
The case was revealed in the company's quarterly statement, in which the firm said the products attracted a total investment of £8.8 million, generating initial tax deferrals of £13.1 million.
Investments in the products 'may result in tax liabilities... in excess of the initial tax deferral' the company noted, following 'announcements from the UK taxation authority [and] the outcome of certain litigation proceedings in respect of the taxation of other similar products'.
In a statement, it added: 'The potential tax liability for those clients engaged in such pre-action protocols which is in excess of the initial tax deferral amount, is approximately $15.6 million (£9.0 million) excluding other costs.'
The company said it 'intends to vigorously defend itself in the event that claims are advanced' and 'believes that such claims would be without merit'.
It added that it may need to provision for a 'material adverse effect' on its finances arising from the outcome of the claims, although it stressed that it was unable to anticipate the size of any liability.
The Times reported in 2016 that Canaccord Genuity was among a number of financial advice firms facing legal action from clients after a crackdown on £200 million tax avoidance scheme Invicta 43, and similar vehicles.
Run by Invicta Capital, Invicta 43 was launched in 2008 and attracted 225 investors, including footballer Wayne Rooney.
The Mirror reported in April that over 100 footballers, including Man United and Liverpool stars, could be looking at a tax bill of over £250 million for investing in film projects.
In 2015, investors including former Lazard International chairman Ken Costa and Investec’s Christian Hess launched proceedings against banks Coutts, HSBC and UBS in relation to film investment schemes run by Ingenious Media.