You can import from more than one financial institution. However, if your account at Bank A is closed, you no longer have a Sign In for that account.
From your electronic copies, you can enter a one-line summary total for 1099-INT/DIV's.
For 1099-B's, here's How to Enter a Summary in Lieu of Individual Transactions. This is perfectly acceptable, since the IRS already has copies of your 1099's.
If you're using TurboTax Online, you can attach a PDF copy of your 1099-B's. Choose 'summary' and you'll come to that screen.
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