Efforts to claw back the estimated $133 billion to $175 billion of previously collected tariffs now deemed illegal are bound to be complicated.

Supreme Court Justice Brett Kavanaugh, in his dissent, warned that "the refund process" for tariffs "is likely to be a 'mess,' " citing oral arguments

The Supreme Court ruling that President Trump's tariffs are illegal will lead companies to seek billions in refunds, but the decision was silent on the issue.