If I were to accept that assertion, how would you measure the total value of a company? Who decides how valuable those 3 year old computers are, how valuable the patents are? How valuable the owned real estate is? The company may assert its understanding of those values, and will do so frequently in financial accounts, but as we have seen, accounts are often restated. Those computers are likely being depreciated by the company, with the depreciation being written off against income. So the company has some idea of what its value of the computers is, but if it were to turn around and sell them, then it might find out that their depreciation model doesn't fit the market for 3 year old computers. What about intangibles such as market share, brand value and employee productivity? Can you measure their value independantly? Again, the company might try to assign a value to those, and again, could very well be wrong. Any value assigned to any component part of the company is open to debate.

My point is that there is no truer value for the company than the one decided by the market, and that value is usually many times the sum of the individual market values of the underlying tangibles. (That's what prevents corporate raiding.) Even when the market appears to be fickle and volatile, that is true.

Here's an analogy.

Supposing you bought an... ipod. A nice 60GB color screen model for $300. Now the individual components may cost Apple $150, but the market value is $300. Do you consider the true value to be $150 or $300?

Now, supposing that the next day, another company enters the market with a 200GB mp3 player that is better in every respect. The kicker is that this other company somehow manages to sell them for $200. Is your ipod still worth $300? I think that you'll agree that it isn't, even though the value of the individual components hasn't changed overnight. If you could get $200 for your 1 day old ipod, then you might be tempted to sell it immediately in order to buy the new player.