It's one month before the 2015 tax filing deadline. I didn't contribute as much as I could have into my 401k in 2015 (I only contributed $8k instead of $18k), but would like to realize as much tax advantage as possible on my 2015 taxes. I've already increased my contributions to ensure I contribute the max ($18k) in calendar year 2016, but would appreciate any input on how to maximize my tax savings on my 2015 filing.
I've contributed $2k to my 401k in calendar year 2016. Is it possibly to allocate or earmark the $2k I've contributed in calendar year 2016 to tax year 2015?
Comparable to an IRA, is it possible to make a retroactive contribution for the previous tax year before the tax filing deadline in the current year?