I had 4 T-notes mature in 2025. Each was bought at a discount and held over a year. I also had mutual fund sales. My 1099-B shows the gains for the T-notes in different column headed "Accrued mkt disc (D)". The sum of the T-note gains is $5465, shown as a positive number. The total gain, T-notes and mutual fund, was $11,992, so the sum of mutual fund gains was $6527. I also had a wash sale of $40 (W), not included in the total gain.
The gain on the1099-B (in the column to the right of "Accrued mkt disc (D)" was $6567, i.e. $6527 + $40. This seems correct to me.
On TurboTax, I checked boxes D and W and entered $5465 (or $5505, I don't remember which) as the adjustment, saved the file and exited.
The $5465 was shown on Schedule B, Interest, with the words "Accrued Market Discount". But on Schedule D, instead of subtracting the $5465 (or $5505) from $11992, it ADDED it to get a gain of $17,457 (or $17497). This meant TRIPLE the income, , once in Schedule B and twice in Schedule D.
I tried again, only checking box D and entering $5465; it did the same thing. Then I entered the $5465 as a negative number and it correctly subtracted it from the $11992. Schedule D showed the $5465 with a minus sign, but Schedule B still had it as a positive number.
I would have thought that TurboTax, having put it on Schedule B, would have known to subtract it on Schedule D.
