Share prices of Tata Power and Adani Power fell today - with Adani Power sinking by double digits - after the Supreme Court set aside an earlier tribunal ruling that had allowed both companies to charge compensatory tariffs from consumers.

The Supreme Court bench of justices Pinaki Chandra Ghose and Rohinton Nariman wrote a verdict upholding the appeals filed against a 2016 ruling by an appellate tribunal. The Tribunal had held that an unforeseen increase in the cost of coal would be a “force majeure event” that would allow price increases under power purchase agreements (PPAs) between power generating companies like Tata Power and Adani Power, and their distributors.

Tata Power and Adani Power had cited a change in Indonesian regulations in 2010 as a force majeure event, which had increased the import costs on coal for fuelling electricity plants. The Supreme Court however ruled that a force majeure event needed to be related to Indian laws, and was not valid outside its borders.