[westurner]

If the market had internalized the external health, environmental, and defense costs of nonrenewable energy, we would already have cheap, plentiful renewable energy. But we don't: the market is failing to optimize for factors other than margin. (New Keynesian economics admits market failure, but not non-rationality.)

So, (speculative_valuation - cost) is the margin. Whereas with a stock in a leveraged high-frequency market with shorting, (shareholder_equity - market_cap) is explainable in terms of the market information that is shared.