Why is my child's investment income of $4,800 triggering over $6,000 in tax due?

[EerinnotAaaron]

My depending child has $4,800 in investment income this year. We opted to not include her income in our return and instead to file a separate return for her. After entering all of the info, Turbotax is calculating that she owes over $400 in federal tax and over $5,800 in CA tax. Huh???? I don't understand this at all.

If we had included her income in our return, it would have added about $600 in tax due.

Thanks for any help.

[BrittanyS]

Have you reviewed the CA return and verified that the income was transported correctly?  You can also preview the 1040 and state return to see where the tax comes from.  

1. From the left rail menu in TurboTax Online, select Tax Tools (You may have to scroll down on the left rail menu.)
2. Select Tax Tools 
   
3. On the drop-down select Tools 
4. On the pop-up menu titled “Tools Center”, select View Tax Summary 
5. On the left sidebar, select Preview my 1040