I thought you were talking about an MLP. There are different codes for different types of investments.
Here is a link to the IRS instrucions:
<a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/i1065sk1.pdf">https://www.irs.gov/pub/irs-pdf/i1065sk1.pdf</a>
Page 15 is where the instructions for Box 20 starts.
