Take the 5 domain sales, chosen to be as representative as possible [no cheating there], average and multiply by the number of names you have in your portfolio. Now this is going to be a huge over estimation of your portfolio worth, but mine is about... £1.2 million. Now to get closer to realisation we need to add some factors in here such as time taken to sell the domains, and the fact that those domains were wanted - hence they sold. I know for mine based on traffic and conservative estimation, I'd be happy with £200k. So who has got the biggest portfolio? We could collect some ideas for amassing net worth of portfolio...could be an interesting little application. However at the end of the day - its only worth what somebody will pay.