The latest volley in the Vanguard Group’s battle to rid itself of a whistleblower lawsuit alleging more than $1 billion in underpaid taxes is a 33-page memo filed last week that underscores the Malvern mutual fund giant’s ardent belief that attorney ethics violations should prevent the case from even being considered by the court.

“Neither the law nor the (whistleblower) exception allow (ex-Vanguard tax lawyer-turned-whistleblower David) Danon to ‘take matters into his own hands’ in hopes of ‘personal benefit’ by failing to go to the top of the company before suing or by disclosing information that should have been kept secret under attorney-client privilege, Vanguard argues,” according to a report on Philly.com.

A district judge for the New York State Supreme Court in Manhattan will consider Vanguard’s motion to dismiss the case on Jan. 22, 2015.

If Vanguard loses that battle, it has also counter-argued that “the Internal Revenue Service and other authorities had the opportunity to adjust Vanguard’s taxes if they had seen any problems with its SEC-approved structure or its publicly-disclosed at-cost service payments,” the article stated.

Read much more about the latest arguments in the ongoing tax controversy on Philly.com here, and check out previous Vista.Today coverage of the whistleblower saga here.