This is our prefered explanation of the origin of the insurance term bordereaux.  The French translated literally means 'at the water's edge', or on the waterfront. 

Early insurance was primarily concerned with shipping losses and the estimation and verification of hull and cargo values would have been concluded on the dockside... au bord de l'eau.  It's obvious n'est pas?

Well, that's our little theory anyway.  We'd be delighted to hear if anybody has differing views.