I became a resident alien but did not update my tax status with my broker in time and they will not retroactively produce the 1099s I need. Instead I will receive a 1042-S. I know my dividend income (and tax withheld on this), and my capital gains/losses, and have my full trade history with cost bases. How do I correctly report the income in my tax filing?
Use the information from your records to enter this where it would go if you did have the 1099-DIV, 1099-INT or 1099-B (for capital gains and losses.) For the "sales section" dropdown box for capital gains/losses select short or long term as appropriate and then choose "did not receive 1099".
If you have withholding from capital gains, check the box "I have other boxes on my 1099-B to enter" (even though you don't have a 1099-B) in order to unhide the tax withholding boxes.