An old 401k was rolled over to an IRA in February of 2017. Can I contribute to this IRA before 4/18 and get the credit for 2016?

[KenH1 · Accepted solution]

Yes, that would count.  Ideally you would open a separate IRA, because the state tax treatment may be different when you withdraw (the rollover money will be taxable but the IRA may not be).  But you are allowed to contribute additional dollars to a Rollover IRA.

[KenH1]

If the IRA is a Roth, then no problems whatsoever

[dmertz]

This answer assumes that one is eligible to make the IRA contribution based on having eligible compensation and, in the case of a Roth IRA, not exceeding the AGI limit.