The book value per share as of the November 2008 10Q is reported to be $24.24. To come up with this number, I subtracted the total assets from the total liabilities and divided the difference by the total number of shares.
Now the main concern that people have about GNW is its exposure to Subprime and Alt A mortgages. FINE! Let us assume that all of these investments went down to 0. Even if we wrote of the entire value of these assets, we would still come up with a book value of $4.74 - almost twice its current value today.
Furthermore, there has been strong evidence in the options market that this stock is ready to break higher.