When I import consolidated from from Vanguard, TurboTax over estimates my interest income. It accurately pulls US treasury interest income from 1099-INT and but also imports the detailed transactions of US treasury sale from 1099-B and add them as additional entry in Schedule B.
I am not sure how can I fix these? Has anyone experienced this?
I have many entry so want to avoid doing this manually, if possible
That sounds like correct handling for discount bonds.
When you sell a bond that was purchased at a discount there will be 'Accrued Market Discount' (AMD) reported in Box 1f. You will also have a gain on the sale. The lesser of these two is considered to be ordinary income and will be adjusted on Form 8949 to reduce the gain and it will be reported on Schedule B. If you had a gain in excess of the AMD that had accrued at the time of sale, then that is a capital gain.
if you hold that bond to maturity then the gain will equal the AMD, and it will all be reported as ordinary income on Schedule B and zero capital gain.
see IRS Publication 550 'market discount bonds':
https://www.irs.gov/publications/p550#en_US_2024_publink100010016
"You must treat any gain when you dispose of the bond as ordinary interest income, up to the amount of the accrued market discount"
and instructions for Form 8949 adjustment in col g:
Yes, I agree with baldietax. In addition to the interest income, there were sales of your US treasury Bonds that is considered ordinary or capital gain income depending on the nature of the sale.