I was able to glean the following from the California FTB web site:
The trustee may have to file a return if the trust meets any of these:
- The trustee or beneficiary (non-contingent) is a California resident
- Gross income is over $10,000
- Net income is over $100
- The trust has income from a California source
- Income is distributed to a beneficiary
Of course, you stated that you, yourself, are a California resident and are the fiduciary (trustee).
