And you thought you had it bad. The Internal Revenue Service (IRS) is claiming Symantec owes it up to $1 billion in income taxes as a result of the anti-virus giant's acquisition last year of storage management vendor Veritas.

But Symantec is contesting the assessment, the company said this week in a regulatory filing with the Securities and Exchange Commission.

The bill is for allegedly unpaid taxes as a result of Symantec's July 2005 acquisition of Veritas for $10.5 billion. The two companies allegedly under-reported the value of a technology license agreement transferred to two Irish subsidiaries set up to sell company products.

"What is at issue is the value of that intellectual property," said Genevieve Haldeman, Symantec spokeswoman. "We believe the tax we have previously paid is appropriate."

Symantec said in the filing that it plans to file a petition in U.S. Tax Court appealing the bill.

"The company strongly believes the IRS positions with regard to these matters are inconsistent with applicable tax laws and existing (U.S.) Treasury (Department) regulations, and that its previously reported income tax provision for the years in question is appropriate," Symantec said in the filing. "The company does not agree with the IRS position and plans to continue to contest these claims in its discussions with the IRS."

An IRS spokeswoman said the agency does not comment on individual taxpayers.