Microsoft has lost yet another appeal in its patent dispute against little-known Canadian company i4i.
i4i maintains that Microsoft infringed its text manipulation patent in Microsoft Word 2003 and 2007, and the US courts agree.
Judges in the case, which has been rumbling on since 2007, have repeatedly upheld the original ruling that said Microsoft should pay a $290 (£170) million fine.
After the regular, juried court made the decision, Microsoft went through the higher courts in order to get out of the fine; the US appeals court upheld the ruling, the US Patent and Trademark Office vouched for the validity of the i4i patent and now the Supreme Court has also upheld the ruling.
Microsoft, which has already set aside the money to pay the fine, still hopes to undermine it with a challenge it has filed on a patent pending at the patent office.
Some might pontificate that it would save the company time and money to just suck it up and pay already, but Microsoft hopes to change the way the courts decide patent infringement has occurred, presumably to protect the company in future cases.
Kevin Kutz, Microsoft spokesman, said, "While the outcome is not what we had hoped for, we will continue to advocate for changes to the law that will prevent abuse of the patent system and protect inventors who hold patents representing true innovation."
i4i, meanwhile, it pretty pleased with yet another unsuccessful appeal: "We're very pleased that the court did the right thing. This is one of the most significant business cases the court has decided in decades."