* What you originally bought it for?
* What you could buy that exact model year for today? From whom?
* What you could buy a similar car for today?
* What you could sell it for? To whom? In how much time?
And that's for something as tangible as a car, listed on the market with easily searched prices. This is a simple example, but I recall that some types of assets (land?) are valued at their original purchase price, which is far deflated from the current market value.
I think of accounting similar to benchmark tools for software -- it's all about what you want to measure, and depending on assumptions you have some wiggle room.
Good points but I think the answer is to pick one (I'd vote #4 but I'm open to debate) and enforce it at a regulatory level. Issues arise when you're allowed to change how you value assets based on what's most favorable at the time.
Ah... but if you do that, you'll be forcing companies to pick an arbitrary measure, regardless of how well it describes the underlying economics. The goal of accounting is description, not conformance.
As a practical matter, this would require the enforcement agency to publish the correct price for every asset regulated.
Publishing a formula for this calculation wouldn't be good enough, because then you would be required to value things based on the formula and that leads you back to...accounting.
I think of accounting similar to benchmark tools for software -- it's all about what you want to measure, and depending on assumptions you have some wiggle room.