W-2 - Box 12 Codes

Elective deferrals from retirement plans and adjustments or deductions are listed with a code and an amount in Box 12.
CODES:
A = Uncollected SS or RRTA tax on tips
B = Uncollected Medicare tax on tips
C = Taxable cost of group life insurance over 50K
D through H,S,AA,BB,EE = Elective Deferrals and Roth contributions
J = Nontaxable sick pay
K = 20% excise tax on golden paachute payments
L = Employee business expense reimbursements
M = Uncollected SS or RRTA tax on life insurance
N = Uncollected Medicare tax on life insurance
P =excludable moving expense reimbursements
Q =Nontaxable combat pay
R = Employer contributions to Archer MSA
S = salary reduction under 408(p) Simple
T = Adoption benefits
V= income from stock option
W = HSA employer contribution
Y = 409A deferral
Z = 409A income
AA = Roth contribution under 401(k)
BB =Roth contribution under 403(b)
DD = employer health coverage
EE =Roth contribution under 457(b)