The adjusted book value adds back (or subtracts) unrealized losses and gains. This didn't affect the adjusted book value too much though.
Another adjustment to get to the adjusted book value is an add-back of the unearned premium reserve. This is what more than doubles the book value. When premiums are paid up-front for a several year period, the cash received is booked as an asset, the amount of premium attributable to the period being reported is booked as income, and the difference is reported as a liability. The thing is, it isn’t “really” a liability. Technically yes, but in reality, no. So it is added back to come to the “adjusted book value.
Monolines have traditionally traded at or above their adjusted book.