Washington State Supreme Court upheld the capital gains tax. In a 7-2 ruling in the Quinn v Washington State case, the majority ruled that the capital gains tax is an excise tax and is, therefore, legal in Washington State. Since it was ruled an excise tax, they did not weigh in on the constitutional questions. This means that tax filers and their CPAs will be required to submit their subjected capital gains taxes by the April 18, 2023, deadline.

Supreme Court Upholds Washington Capital Gains Tax as an Excise Tax