I think @TomYoung is over explaining.
The answer is, the $ from the 16 shares is already included in Box 2 on your W-2. Check your pay stubs. When the shares vested, you got a stub saying that amount was for federal withholding, and if you add up federal withholding from all your pay stubs, it will equal the amount in Box 2.
@TomYoung is discussing a completely different point, if I can paraphrase what I think I understand and @TomYoung feel free to correct...
your Box 1e on your 1099-B might need to be corrected. Box 14 on your W-2 reflects the true cost per share cost basis. Divide the Box 14 amount by the total number of shares released (that is including the ones sold) and that's your per share cost basis. Then check "My cost basis is wrong" and enter the number of shares times the per share cost basis.
There's three possible outcomes:
- If 1e was reported $0 then yes, this will significantly reduce the tax owed.
- If 1e was reported as the value at the time of the sale, and:
-- the W-2 per share cost basis is higher, then the adjustment reduces your tax owed by the difference
-- the W-2 per share cost basis is lower, then the adjustment could actually increase your tax owed, in which case, I don't really know if legally you can be punished for not making that correction. @TomYoung?
