Savvysoft, a US-based financial software company, said that it is facing a trademark infringement challenge by Microsoft over the use of the term 'Excel'.

Rich Tanenbaum, founder of Savvysoft, claimed that Microsoft has never been granted a registered trademark on Excel, and that the legal challenge against Savvysoft's TurboExcel spreadsheet acceleration and migration tool is invalid.

"In fact, [Microsoft] waited 19 years just to apply. Plus, there are over 100 third-party products with Excel in their name," said Tanenbaum.

"Microsoft's own website actually offers downloads of over a dozen products with Excel in their name that are offered by third parties.

"As any trademark lawyer will tell you, when you've got a trademark, and you let other companies use it, you lose it."

Tanenbaum went on to say that Microsoft's own trademark website lists dozens of trademarks but does not mention Excel.

"Microsoft's actions over the years have been consistent with that of a company that does not own the Excel mark," said Tanenbaum.

"We can fight Microsoft and spend half a million dollars or more. Or we can pay $100,000 to replace all our sales and marketing material and redo every bit of publicity. Even then, you can't put a dollar value on intangibles like goodwill and brand recognition."

Microsoft dismissed the claims, issuing the following statement: "Excel is a very well known spreadsheet product and is readily identified as a Microsoft product. It's important that we protect our trademarks from being used in a manner that could cause consumer confusion.

"We have common law trademark rights to Excel based on our usage of the name for nearly two decades."