I just did a position transfer of my investment brokerage account. Since this is a mid year transfer, I want to understand the tax filing implications. When I file taxes for this year, would I need to obtain tax documents from both brokerage firms ? Or will the new firm's tax documents contain the entire history of my transactions ?
Your old firm will report market transactions if any on the 1099 and issue you 1099-B statement separately. New firm will be not liable to report transactions from the old firm. You should wait for the year end to receive statements from both firm.
If your account is going to be deactivated with the old firm. I suggest get in touch with the administrator and make sure the 1099 statements are delivered on year end to you.