What is the biggest tax refund ever?

Answer 1

Any refund over 2 million dollars must be approved by the joint committee of taxation of the congress.

There are thousands of those alone each year.

The amount of the largest refund will never be known as ll IRS info regarding a taxpayer is strictly confidential. Certainly many refunds of 100s of millions have been made over the years (most likely all to corporations who may also pay many times that on any given year).

Answer 2

The biggest tax refund ever issued was $12.1 billion in 2019. This was a result of the U.S. government over-withholding taxes from individuals, and the refund was paid out to correct the error.