If contributed excess to traditional ira but didn’t report excess on 2016 filing and also have not taken excess out yet, do I need to amend 2016 or can I correct on 2017?

[brian_c_hawkins]

Contributed 5,700 but only reported max 5,500 In 2016

[dmertz]

You need to amend your 2016 tax return to report the $200 excess contribution made for 2016 and pay the 6%, $12 penalty.  Unless you can apply this $200 as part of your traditional IRA contribution for 2017, the excess must again appear on your 2017 Form 5329, subject to another 6%, $12 penalty.  If you can't apply it as part of your 2017 contribution, to avoid another 6% penalty for 2018, you'll need either be able to apply it as a 2018 contribution or obtain a regular distribution of $200 from your traditional IRA, taxable and subject to a 10% early distribution penalty.  A return of contribution after the due date of your [2016] tax return is not permitted to be nontaxable because your contribution in 2016 exceeded $5,500.

If you made the maximum traditional IRA contribution for 2017, you can obtain a "return of contribution"(not a regular distribution) of $200 of that contribution, with the distribution being adjusted for any gain or loss, to make room to allow the $200 excess from 2016 to be applied as part of your 2017 contribution.