also notice how the difference between NTA and book value is...

also notice how the difference between NTA and book value is constantly being written down. This implies that the underlying business units never lived up to their acquisition premiums and "management internal forecast profits are not being achieved, nor are they expected to achieve in the future" hence the "write downs"

This is why I always suggest running any analysis of NTA and not book value".

The NTA is essentially the float used to write insurance policies. The book value minus NTA is the imbedded management value of the business divisions.