The U.S. government took legal action Tuesday in an attempt to collect the $1.5 billion it says Yahoo successor Altaba Inc. owes in taxes.

Counsel for Altaba, a Delaware corporation operating out of New York, wrote in a May Delaware Court of Chancery petition that the Internal Revenue Service’s claim is inflated, with about $659 million being the amount the company is willing to hold back for federal tax liabilities while finalizing the dissolution its board agreed to last year.