BRUSSELS — An appeals court on Thursday upheld an antitrust fine of 1.06 billion euros against the computer chip giant Intel, giving more teeth to the European Union’s power to hold multinational technology giants accountable — even if the case is years old and Intel no longer wields the sort of power over consumers that got it into trouble in the first place.

In its ruling, the General Court said the penalty, an amount now equivalent to $1.44 billion, was proportionate to the company’s anticompetitive behavior. It is the largest antitrust penalty that the authorities in Brussels have levied on a single company.

Chuck Mulloy, a spokesman for Intel, said the company had 70 days in which to decide whether to appeal to Europe’s highest court, the European Court of Justice.

Five years ago, the European Commission, the executive arm of the European Union, found Intel guilty of misdeeds that included paying rebates to personal computer makers like Dell and Lenovo for favoring its chips over competing ones from Advanced Micro Devices, Intel’s chief competitor in PC chips.