The lender said the claim related primarily to Grant Thornton’s advice and audit services, associated with the implementation and application of hedge accounting.
Manchester BS said if it was unable to reach an agreement with the accountant it would take the dispute to a court hearing.
A spokesman for Manchester Building Society told the BBC that it was forced to restate its 2011 results which turned a small profit into a loss of £21.9m for the year, due to poor and incorrect advice given on how to account for interest rate swaps.
It also made a loss of £2.3m according to its 2012 results and was required to raise £18m to reinforce its finances in April 2013.
An investigation carried out by the Financial Reporting Council into Grant Thornton’s practices began in August 2013 following information received from the Prudential Regulation Authority.
A spokesperson for Grant Thornton UK said: “As a large professional services firm, there are inevitably occasions where we become involved in legal claims. Naturally, our obligations of confidentiality mean that we cannot comment on the detail of any litigation in which the firm is involved.”
Manchester BS were unavailable for comment at the time of writing.