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Level 4
April 8, 2026
Question

Reporting wash sale from 1099-B

  • April 8, 2026
  • 1 reply
  • 5 views

When I report a summary of my transactions from my 1099-B, do I have to adjust the basis with "W" and put in the wash sale disallowed amount from box 1g in as the new adjusted basis? It seems to make a big different in taxes owe since my total transactions has a net loss. Adding the "W" and setting the wash sale total as the new basis significantly increase my taxes owe. Is this expected?

1 reply

Level 15
April 8, 2026

Don’t include the wash sale in the summary. Enter it by itself with a code W. 

yatoshuraAuthor
Level 4
April 8, 2026

I have several hundred transactions. My Fidelity 1099-B shows a summary of all the transactions along with their proceeds, basis, wash sale, etc. Should I single out all the individual transactions with wash sale separately from the rest of the summary? Does it make a difference?

When I input the summary, it also let me check the "W" box and put in an adjusted cost basis. Is this not the wash sale amount in box 1g?

CatinaT1
Level 15
April 13, 2026
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