How do I handle a wash sale if it involves two unrelated brokerage accounts? The first will issue a 1099 showing a loss; the other has no visibility to the sale.

[BillyD2]

The sell / buy of the mutual fund was done on the same day.

[Mike9241]

you'll have to do it manually. neither the brokerages nor Turbotax can do this.

[ErnieS0]

Enter your sales manually as Tax Champ Mike9241. In answering your question, I’m assuming your first sale with Form 1099B will show a loss without a wash sale.

When you enter your transaction, check the box The cost basis is incorrect or missing on my 1099-B.

On the screen, “We noticed there's an issue with your cost basis...Let us know if you'd like to make any changes” choose I know my cost basis and need to make an adjustment

Enter your cost minus your wash sale.

In your second transaction, if you do not have a 1099-B, enter the correct cost basis with the wash sale amount. If the second sale is reported on Form 1099-B, repeat the process with your first transaction, but add back the wash sale amount.