What are Property Casualty Insurers Worth?

Last week, Harleysville insurance agreed to be acquired by Nationwide for $60 per share, which works out to $1.6B or about 2x book value.  Prior to the news, HGIC was trading at about half that level.

P/C insurers have been beaten up with the rest of the financial sector and trade near historically low valuations.  Below is a list of the 25 largest insurers and their P/B multiples.  If 2x book is the right price to pay for a regional P/C business, then there could be some low hanging fruit here.