Sounds like CA wants copies of whatever 1099's you entered on your tax return. You do not say what kind(s) of 1099's you entered. There are over a dozen kinds of 1099's so it is important to mention to us what kind you received. Did you receive a 1099NEC? 1099Misc? 1099G for unemployment? 1099B for stock transactions? 1099DIV for dividends? 1099INT for interest? Etc, etc. etc.
Read the letter you got from the state very carefully and then provide the state with copies of the documents they want. The state has the right to request copies of your tax documents. The sooner you provide the information the state wants from you, the sooner your return will be processed and the sooner you can receive the state stimulus if you are eligible for it.
You do not calculate the federal refund for unemployment you paid taxes on. The IRS will calculate it for you. And CA does not tax unemployment so there is no issue with CA regarding unemployment. If you filed your tax return early before the tax law changed in March of 2021 then the IRS is recalculating and issuing "extra" refunds for the tax paid on the first $10,200 of unemployment. You do not have to amend for it.
The IRS is recalculating refunds for people whose AGI is $150K or below and who filed before the tax law that changed the amount of unemployment that is taxable on a federal return became effective.
The IRS began to send out the additional refund checks for tax withheld from unemployment in May. The refunds are being sent out in batches—starting with the simplest returns first. If you are eligible for the extra refund for federal tax that was withheld from your unemployment the IRS will be sending you an additional refund sometime during the next several months. TurboTax cannot track or predict when it will be sent. The IRS has not provided a way for you to track it, so all you can do is wait for the refund to arrive.
https://ttlc.intuit.com/community/tax-topics/help/how-do-i-get-the-new-unemployment-benefits-if-i-ve...
Please read this very recent news from the IRS:
https://www.irs.gov/newsroom/irs-to-recalculate-taxes-on-unemployment-benefits-refunds-to-start-in-m...
https://www.irs.gov/newsroom/irs-begins-correcting-tax-returns-for-unemployment-compensation-income-...
https://ttlc.intuit.com/community/tax-credits-and-deductions/help/am-i-eligible-for-a-new-credit-or-...
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
