How about this alternative way of measuring the 'value' of a company: Net asset value (including retained earnings) plus the sum of all dividends ever issued, minus total investment capital.
Most companies don't trade at book value because net asset value is a bad measure of market value. Getting a mark-to-market assessment on a firm's entire balance sheet is very expensive and still resorts to estimating market value rather than directly sampling it.
One could do equity value + discounted payouts - discounted invested capital. This includes payments on debt and possibly taxes.
This measure would not be a "value" in an economic sense as valuation is in present terms, incorporating future potential and using the past only to inform assumptions. This measure catalogs a company's time-integrated capital productivity. This could inform a valuation, but taking an extreme case, it would value dearly a shell company that just paid its assets out in a dividend.
With the subjectivity complexities like cross-border activity or M&A introduce the exercise has little value beyond the pedagogical.
The dividends issued historically are gone, entirely separate from the company. Assets and liabilities can exist in different forms, including tricky ones like depreciation and intangible assets. If such 'value' is accounted for important uses, manipulating it will be much cheaper and easier than manipulating market cap anyway.
Sure, it's hard to measure the value of assets. But look at it this way: In the long run, every company dies, so assets always go to zero. What investors (in aggregate) are left with is the net sum of dividends paid out.
To answer "what is the most valuable company in history" I would look for the company which paid out the most in dividends before it expired. Stock price is largely a measure of which company has managed to attract the most suckers.
Don't know why people would downvote this. It's a pretty good idea of how to measure the value of a company. It's somewhat shy of the true metric which would be along the lines of 'how much better it made the world'. Market cap is appealing because it's trivial.
These definitions would also allow comparing non-standard corporations, like churches and states. It seems like this is a natural comparison - it's inevitable that big companies are ranked among comparable countries.
