That NTA includes illiquid investments that are very hard to value. I think there is a 20-30% low risk upside but it's starting to get speculative after that.
Unless you could accurately value Baycorp or Signature then you'd have to take a fair whack off the value (OCP uses book value and only has to write that up or down in certain circumstances).
It's been fun but the upside is drawing to an end!