By my calculation, wholly owned subsidiaries are approaching a 100% premium to equities. Never has this ratio been this year.

Yes, equities are lower than they were as a portion of the pie. (I'm not sure what you mean as "premium", but no matter).
The change isn't huge, though, compared to various times in the past. Given that book has so far tracked value pretty well, one can estimate it that way: equities are 41.8% of book in these statements versus for example 46% at end 2012, 48% end 2014, 43% end 2016, 49% end 2018.

But I apologise, my reply was slightly off topic, speaking of the ratio of value from operating subsidiaries, to TOTAL value. i.e., the ratio of value from operating subs to (operating subs + all investments per share). On that view, I was just pointing out that the relative importance of operating subsidiaries has been flat to falling, not rising, for a very long time now.

In part this is simply because there haven't been any big acquisitions since BNSF, and maybe never will be again, so investments stack up while operating earnings lag in terms of growth rate. One would hope that small(er) acquisitions would offset this, but that doesn't seem to be the case in the last 15 years. The investment portfolio (cash, fixed income, and equities) has been becoming a larger part of the story. In this stretch, anyway.

Jim