The net tangible assets of RHG Limited may be only half the value stated in the company's accounts, or A$66 million rather than $123 million.In a parting essay, in the annual report for RHG, the chair, John Kinghorn, provided an overview of the issues relating to the valuation of collateral provided to banks financing the warehouses that fund part of RHG's residual home-loan book.According to Kinghorn, the treatment of $57 million in collateral and subordinated debt at historical cost rather than market value is a problem given that most of these funds will not be available to the company for 10 to 15 years - and only then assuming there are no losses on the remaining loans.On the other hand, Kinghorn notes that the NTA calculation does not allow for the present value of cash flows servicing the declining mortgage book of $3.5 billion (though the costs of servicing will exceed income from 2018). The NTA per share of RHG, based on the accounts, is around 40 cents per share. RHG's shares are also trading at around this price, down from a recent peak of 56 cents in early September.Most likely a buyer will be found for the rump of RHG, which ceased originating new loans in late 2007 and sold its Rams Home Loans brand and franchise network to Westpac at the same time.Kinghorn will leave the board of the company he founded 20 years ago at the annual meeeting.