Capital gains when filing separate state returns

[mover20]

My wife and I both lived in Texas in the beginning of 2019, but I accepted a job in Maryland in April 2019. We've decided to live apart for a while so only I moved to Maryland. I had an stock investment account that I transferred to my wife in March so she could take care of the investments from Texas. If we file a joint federal tax return and individual state returns, do I need to show capital gains from my wife's investment account on my Maryland state return?

[MaryK4]

If you are filing the joint return for federal but separate for Maryland, you must attach a pro forma Form 505 and Form 505NR and only she would report the income on the NR.

[mover20]

Would my wife owe taxes on income reported on Form 505NR? 

[MaryK4]

Only your wife's Maryland state-source income would be taxed by Maryland- so the interest and dividends would be Texas income.  @mover20