The only change effective October 1, 2020, is the Missouri refund rate, which dropped from 1.90% to 1.80%.

Three changes effective January 1, 2021, were implemented:

• Idaho will reduce its rate from 4.00% to 2.00% for both overpayments and underpayments.
• Kentucky will reduce its rate from 7.00% to 5.00% for underpayments and from 3.00% to 1.00% for overpayments.
• New Hampshire will reduce its rate from 7.00% to 5.00% for underpayments and from 4.00% to 2.00% for overpayments.

Two changes effective January 1, 2021, were implemented in previous versions.

• Colorado reduced its rate from 9.00% to 6.00% for both overpayments and underpayments
• Kansas reduced its rate from 6.00% to 4.00% for both overpayments and underpayments.

A correction was made to the refund rate for Pennsylvania effective January 1, 2020, from 2.00% to 3.00%.