Due to the Tax Reform Act having significantly reduced federal tax withheld for a given number of withholding exemptions, I decided to change my W-4 withholding category from Married to Single, in order to withhold a sufficient amount of tax.
Consequently, my last pay stub of the year went over $200k of Medicare income, and having checked Single on W-4, my employer withheld some Additional Medicare Tax.
Because I will file Married Jointly, I am not subject to Additional Medicare Tax as my income is less than $250k.
I looked at Form 8959, but don't see where/how I can claim a refund of this additional Medicare tax withheld.
Meanwhile, I did just change my W-4 to check the box, Married, but withhold at higher Single rate.
Please advise what I can do to recover the additional Medicare tax that was withheld.