“The verdict is a stinging rebuke of how the tax agency and the administrative court have behaved,” Sven-Olof Lodin, a professor of fiscal law and author of several books on taxation, told the news agency.

The legal battle was the first in a string of similar cases and likely to set a decisive precedent between Sweden’s tax agency and private equity firms, which were facing more than 4 billion Swedish crowns ($612 million) in back taxes.