something is wrong. the brokerage where you bought the shares reports the purchase and sales dates to the partnership. Based on those dates it determined that 90% of shares were held long-term and 10% were held short term. That's what the 1099-B should show 10% as code B in the short-term section and 90% as code D in the long-term section. sometimes a brokerage will also provide you with an unofficial "1099" report by security. look at the 1099 what dates, purchase and sale, are being used for the lots. codes B and D merely tell you that proceeds but not tax basis were reported to the IRS. B for short-term and D for long-term it is the brokerage's responsibility to properly report to the IRS based on holding period so what code is the 1099 using for the lots. if in fact all the shares were held long-term you would need to contact the partnership for a corrected sales schedule. it probably won't change anything and if the partnership has bad dates, rather then wait for a corrected sales schedule which the IRS does not get report all as long-term.
if 90/10 holdings are correct split the proceeds and tax basis 90/10 and use code T for both
from 8949 instructions
You received a Form 1099-B (or substitute
statement) and the type of gain (or loss)
shown in box 2 is incorrect
use code T
Report the transaction on the correct part of Form 8949,
and enter -0- in column (g) on that part of the form if there
are no adjustments needed for the transaction.
