HSA - only your portion of any HSA contribution (what's taken out of your paycheck) would reduce box 1 of the W-2. if the employer made the entire HSA CONTRIBUTION, box 1 wouldn't be reduced. box 12 would still show the amount as code W. the amount appears on form 8889 line 9 and you would get no deduction since, in this case, it was employer contributions and not deductions from your paychecks. if there were deductions from your paycheck for the HSA box 1 should have been reduced. the 8889 works the same way, you get no deduction because your taxable wages have been reduced. both the employer's match and your contributions would show up as code W and flow to line 9 of the 8889.
