The basis of your partnership is not tracked by the brokerage company, as it needs to be adjusted for income and losses passed thru to you during your ownership, this is why it is not reported on the 1099. You need to calculate yourself by taking the original cost that you paid for the partnership interest and adjust it up or down for income and losses that were reported on your K-1's since your ownership. Most partnerships now provide in supplementary information with the K-1 which provide the basis adjustments needed to your original purchase.
