Hi. I had a negative adjusted basis on a different PTP. But first..
Disclaimer: Not an accountant, attorney, tax preparer, IRS Agent, etc. The following is for entertainment purposes only. Use at your own risk.
Bottom line: the negative adjustment will decrease your basis. If your sale proceeds are $300 and your adjusted basis is $-100 your net proceeds will be $400. In my case, there was a K-1, Part III, Box 11, Code C loss (Section 1256 Contracts) which flowed to Form 6781 and Schedule D and "offset" the "false gain" resulting from the adjusted negative basis. In my case, the final calculations were in line with the loss calculated from Brokerage information alone. Turbotax will calculate things correctly.
Now, how do you enter the negative basis? See my post here: https://ttlc.intuit.com/questions/3735239-negative-basis-on-sale-of-ptp-reported-from-broker-on-1099...
Also note that you may not have to enter a negative basis if you have multiple sales of the same PTP (same Brokerage) that cumulatively yield a positive basis (e.g. Sale 1 Basis= -100, Sale 2 Basis=300, Total Basis = 200). The Sales Schedule of my PTP (ProShares) includes the following language:
"IRS Revenue Ruling 84-53 provides that a partner has a single unified basis in their partnership interest (emphasis added). If you acquired your partnership interest through various purchases, each row on the schedule above includes a prorated amount of each acquisition reflecting the unified basis of the disposed partnership interest."
I took this to mean that I could aggregate the sales and report them as a single transaction on Form 8949. In FORMS, I modified the 1099-B worksheet and used "Various" as the acquisition date, and date of the last sale as the sale date. They were all short term transactions. The basis, proceeds and gain/loss results of the aggregated transactions are, of course, identical to the totals from single transactions so I think/hope the IRS computers will be happy. If they're not, I have documentation indicating that all is in order. Good luck!
