Box 12 Code W

[Bjnigg]

On my W-2 I have an amount listed under Box 12 Code W. When I enter that amount in Turbo Tax. It increases my federal tax burden by about 30% of the amount and my state tax (Oregon) burden by about 10%. 

Why would entering any amount here increase my tax burden? 

[dmertz · Accepted solution]

TurboTax treats the code-W amount as an excess HSA contribution subject to tax and penalty until you complete the HSA section of TurboTax to indicate your eligibility for an HSA contribution.