NQSO Withheld in 2 States

Hi,

 

I just file my taxes, but realizing I may have done them incorrectly.

 

I received some NQSOs a number of years ago while living and working in Colorado. While there, those NQSOs we're vested, but not yet exercised. I since moved to a new state, but continue to work for the same company. I typically just need to file one state tax return (for the state where I now reside).

 

When I exercised some of those NQSOs, taxes were withheld for 2 states: CO and my current state. When I filed my taxes, I filed in both states. For Colorado, I simply reported the income earned for that state as was on my W2 (thinking that though I haven't lived or worked in that state for years, I was given the NQSO grant while in that state). Now that I've thought about it more, I'm thinking I should have entered $0 for income earned in Colorado and gotten a full refund for the withholding held for the NQSOs that I exercised. Is that correct? Or did I file correctly?

 

If I did it incorrectly, should I amend my filing to correct the issue? It means a larger return for me, but really just want to make sure it's done correctly and not be audited.

 

Thanks.