I agree NSC does have a more concentrated portfolio in smaller...

I agree NSC does have a more concentrated portfolio in smaller cap stocks which would not be to everyone taste.
I would not read much in today's SEC SP jump which tends to be more volatile and trades on small volumes.
NSC trading has a lot more depth and much smaller bid-ask spread.

Buying SEC at a 25% or 10% discount to NTA is no brainer. Buying (or even holding) at post-tax NTA is a different proposition.
You certainly need a lot of faith in the management to outperform its index (after fees).
Curious to see what management reaction will be to SEC trading at post-tax NTA. Will they issue options to increase their FUM (and fees!)? It's quite fashionable lately (WGB, PGF, FGX, PIC....).

A potential catalyst for NSC to close its gap to NTA is Geoff Wilson's activism.
Among all the LIC in WAR, the ones trading at the steepest discount (~20% pre-tax) are NSC and OZG.
In just a few months he managed (through merger and structure change) to get APL and TGG trading back to post-tax NTA.
Once he is done with the PAF takeover I could see NSC being his next target. Maybe getting NAOS to consolidate NCC/NSC/NAC and change the structure of these LIC?