monkeys and ponies

It's not simply a matter of making a list, or even checking it twice. Generally speaking, assets are valued based on a market. If you, say, have 100 shares of AT&T, you can look it up at any moment to see how it's valued. But suppose you own a mortgage. Well, you can look at the interest rate and length, and then compute a present value. But some percentage of mortgagors default. So you build in an assumption related to the cost of foreclosure. But how much is the underlying real estate worth? You know what the mortgagor paid for the house. You know what other people paid for their houses and what they're selling them for. But suppose -- just suppose -- the housing market drops suddenly and precipitously. What's your mortgage worth now? Any time you're dealing with illiquid assets (i.e., assets for which there is a limited market), or where conditions are changing so fast that financial models no longer are reliable, you really can't know what an asset is worth.