Investors & landlords

Your suggestion at the end is correct for SXL.  When ETP bought SXL, your SXL units became ETP units.  And the passive losses you had for SXL became ETP passive losses.  So when you get to the ETP question about suspended losses from last year, you'd add together what you had from ETP and from SXL.  Then you can delete the imported SXL from your return.

On PTXP, it depends on what ETP did with them.  If they were absorbed like SXL, the handling is the same.  But if ETP simply divested the stake in 2017 then that should have been a complete disposition from your end back in 2017.

For a different case, ET has now absorbed ETP BUT has kept ETP alive as an ongoing entity.  In this case, the ETP passive losses from its standalone days just stay with it under the ET umbrella, since PTP continues to stand as a legal entity..

Finally, in the case where SUN was part of ETP in 2016, but not in 2017, handling could happen a few ways depending on what specific information ETP provided in their K-1 package about the disposition (they'll explain it there or with the reps at taxpackagesupport) AND whether you own SUN outside of ETP.  If for example, ETP sold their SUN stake and you don't own it anywhere else, that would qualify as a complete disposition of SUN.