1. Enter the dollar amount for interest.
2. Yes, California treats an HSA as a regular after-tax investment account, so enter the dividends.
3. In a mutual fund, capital gains can be generated when the fund buys and sells stock. This happens all the time, not just when you liquidate investments. This is definitely different from interest.
4. I do not know if Optum will send you a tax form (like a 1099-Combo) as a financial company would for an after-tax investment account. HSAs are pre-tax in 47 out of 50 states, and I don't know to what extent HSA custodians go to accommodate the taxpayers in the other three.
Do the best that you can in finding the interest, dividends, and capital gains. You might call Optum and see if you can speak to a customer service rep who is familiar with the three states that don't recognize HSAs (California, New Jersey, and Alabama), to see if Optum can optionally provide a statement that will assist you.
