This happens to be an S corp that gets a K1 from a multi-state LLC. Share of liabilities dropped by end of 2018, creating a large excess of basis gain at the S corp level.
Any reason to decide how much (if any) of that gain to report to each state, any differently that a partial sale by the S corp of it's interest in the LLC would be reported? It's a pita and some guesswork to look at latest rules for a whole bunch of states on partial sale of an LLC interest. Safest would be to apportion same way as current year biz income to each state. But the state of domicile and the resident state for all the shareholders, CA, probably would disagree.
If you know of a list in RIA or CCH for which states expect apportionment of the gain and which don't, please let me know.
Len Raphael
Oakland CA